The year is 2022, a highly hyped game called Sword Art Online just released after beta testing. Your son decided to wait in line for the game on release date, and upon getting it, decided to play it right after he came home from getting the game. You feel a bit disturbed since the equipmen that the game requirest, NerveGear, intercepts all body commends from the player while the player is in play, making the player unable to move physically while he is in play. Nevertheless, knowing how long he waited for the game and how much fun he has playing MMORPG, you let him play.
Few hours later, new reports describe Sword Art Online and how it is preventing users to log off and if the NerveGear was taken off forcefully, would kill the player right away. Knowing that your son is now basically fighting in game for his life, as his life will end if his hp reduces to 0 in the game, you want to help and save your child but is scared to do so since of the new reports of family member taking off NerveGear and killing the player in the process. Now, using what we know and assuming the technology behind the whole NerveGear and SAO system, lets run some possible methods to save the players without having them to finish all 100 levels in the game.
What we know and can deduce from:
We know that the players themselves can’t log out from the game using the menu, and can’t move their bodies (aside from critical actions like breathing and blood-flowing), and if the NerveGear is taken off before the 100 level are completed, the headgear will emit microwaves, frying the player’s brain. We also know that during the beta phase, this was not the case, since the male lead, Kirito, was able to log on and off normally and often enough to be well versed in the game during the beta phase. This added with the fact that he is using the same NerveGear during the incident and during beta testing, it is safe to assume that there are some mechanism inside the NerveGear that enables and disables the brain frying ‘function’. Also to keep track that the helmet is being taken off, there should be some sensors that either keep track of any kind of movement to the NerveGear (ie gyroscope) or a scanner that keeps track of the position of the player’s head.
From the anime, we also know that several people have already died from the incident, some precisely because of their family members/friends taking the helmet off. While this means the death of those players, it also means that some of the headgear is taken off and can be used for examination. This might mean that rest can be easily saved if the investigators can find an easy way to render the helmet useless.
The main purpose of the NerveGear is to display the virtual reality and to receive actions from the player, most likely sending it to the SAO servers. It has a battery of it’s own, and guessing from the anime, if it reaches a certain battery level (because it being disconnected from a power source), it will proceed to fry the player’s brain. On top of that, there might be some other possibilities that the headgear will decide to fry the player’s brain just to make removing it harder. For now, I will assume that the device will also fry if NerveGear cannot connect to the Internet for some time (sorry, people with bad, laggy internet) and that the device is tamperproof, and hence will fry if someone starts messing around with the innards of the gear while the user is still wearing it.
Also, since the only possible method for the player to actually return back to real life alive is to finish the game, and assuming that Akihiko Kayaba is not lying that part, it also means that the NerveGear can take a particular command from the SAO server and deactivate the brain frying function. At the same time, if the server realizes that the player has died in the game, NerveGear will receive a particular command from the server to kill the player.
With all that figured out, let run some possibilities that can save your son:
1) Use tinfoil, or other types of foil that will block RF: This is the most obvious solution, but is quite risky. The idea of this method is to slowly put such sheets between the player and the NerveGear, as much as possible, before removing the gear, in hopes that when the NerveGear does start to fire off brain killing waves, those sheets will prevent it from entering from the player’s brain, and if it did, will not be strong enough to kill the player. The problem with this method is 1) the success of it is based highly dependent on how effective the sheets are against the microwaves 2) if it is even possible to cover the player’s brain fully for it to be protective enough (especially since the NerveGear covers the whole head, making slipping to cover the whole head quite hard) 3) the problem of triggering the microwave because of head movements that might accidentially happen when the protection sheets are placed on before enough are in place to protect the brain. Therefore, while it is possible, it is still highly risky.
2) Use a man-in-the-middle + reply attack: Since the NerveGear can receive a certain command that enables and disables the brain frying function, researchers can try to create that command, send the command using man-in-the-middle and fool the NerveGear that the player has finished the game and will proceed to disable to deadly function. Obviously the researchers can’t just grab the particular command from the author, Akihiko Kayaba himself (or maybe they can), they can try by observing the data that was passed to the NerveGear from the start of November 6, and seeing if they can find when and which command it is that caused the NerveGear to enable the function, then predict the code that can disable the function. If the message is something as simple as “change the trigger”, researchers can just use reply attack and send the same packet and stop the function. Obviously, if the message that enables the function is encrypted (and I won’t be surprised that it is), unless it used a very crappy encryption scheme, creaking it and creating a new message to disable the NerveGear’s death transmission signals will be hard.
3) Disable the whole NerveGear itself: Since the death of several gamers, researchers can use the helmet of those gamers and research the inside of the headgear, hopefully finding where the CPU is. Then knowing the location of the CPU, researchers can just destroy the CPU of the device and then proceed to remove the helmet without fear of killing the player. This is possible since any information must be first processed by the CPU before instructions can be handled out. For example, if the battery reaches to a certain level, the sensor will recognize this and will provide the information to the CPU, then finally the CPU will send out instructions to send out death microwaves, without the CPU, the NerveGear would never send out the death microwaves. Without any kind of tamperproof, this process is just a walk in the park, since the researchers can send all the time they want to open up the NerveGear and render the CPU useless by smashing it for example. With tamperproof, speed and precision comes into play, as the CPU must be smashed before information about the headgear being tampered with is received and processed by the CPU. In short, the method is to just destroy the NerveGear enough so that while it can’t do anything, it will also not blow up while the player is still wearing it.
3.1) Shock the NerveGear and fry components. There is a Chinese saying that states “Fight poison with poison”, and since the NerveGear is trying to fry us, we will just use the same tactics on it to fry the NerveGear. If the helmet is not tamperproof, just open the helmet and pour water on the motherboard, which will fry the motherboard and make the whole system useless. If the helmet is tamperproof, just provide more current to the player than it requires, which might end up frying the system also (though I think there are ways the NerveGear can get around that method). So while not guaranteed, it have a high chance of succeeding, especially since the NerveGear itself is a computer. Source: http://www.ehow.com/how_2292999_fry-motherboard.html
4) Stop time, remove helmet, resume time. Now don’t we all wish there is a Homura near us.
I have skipped on the less technical and more law based resolutions (ie suing the company and Akihiko Kayaba for the whole incident, but the company will likely deny any relations to the whole incident and say only Akihiko was behind it [which I obviously don't buy, since the whole system that enables the current state involves so many different parts of the project (NerveGear, menu UI, the servers etc), and for a project as big as SAO, it would have involved many teams on QA, meaning that it would have took several teams to implement the system, several teams of testers to either turn a blind eye of the potential issue and/or having the higher up covering the whole issue during development], and/or trigger Akihiko to just end the lives of all the gamers with a potential red button that he might have programmed.
Out of the four possibilities (the 5th one is just there for jokes), I think I would trust the 3 and 3.1 the most, since they can be done in a more timely matter (less chances to die in game) and can have less risks than the other two. So remember, when you kid does go into such situation, just destroy the darn headgear.
Now, dear readers, what do you think, how efficient the methods that I have stated are, and what are some method that you think would work and save your love ones?

I’m sure Kayaba bribed tons of government officials to turn a blind eye during testing and regulation phases (not to mention all the workers during even manufacturing and programming), but even so, people can still reverse engineer NerveGear’s inner structure by disassembling unused NerveGears or simply looking over the factory plans…
However, disabling the NerveGear might be difficult: instead of having one CPU that controls everything, I’d expect Kayaba to add one CPU for gaming/nerve regulation interfaces, and an extra side-computer to immediately fry the gamer’s brain should anything happen (which would suck for people whose power goes down after a tsunami).
tl;dr: what if apple secretly implanted RADIOACTIVENESS into every iPhone ever?!?! then they can like, radioactivate the whole world
It one thing to bribe the government and other people so that the NerveGear can even be sold, it is another thing for someone to look at the device at design stage and question something like “He wants me to have a mode which will intensify the waves so that it can fry brains. And why?” And with a project as big as SAO, with the company doing both the hardware and software, meaning that there should be quite a few people behind this project, I’m surprised that no one in the project was able to pick up something fishy about it, do some kind of whistleblowing and deliver the whole thing before release. Yes, while that is directly going against the Kayaba, recall that he is only the project lead of the game, not someone important like the CEO or board member. Knowing that the company might fold because of this incident, would an average employee just sit there and let the product be released? Therefore, in a way, while technologically the whole SAO incident is possible, it is just very rare for it to happen without any hint of it before release.
Even if there is an extra CPU that does the separate tasks, as long the chain of command is broken that cause the brain frying, the player is theoretically safe (barring the whole device blowing up on their head). So if we fry the whole device as per 3.1, # of CPU would not matter. For solution 3, the researchers can just destroy both CPU simultaneously, or experiment and see which one is used for brain frying (pity for the few that died because the researchers guessed the wrong CPU), that is assuming that the function of each CPU doesn’t differ per NerveGear [as that will add another step to manufacturing].
tr;dr The company should have just fired Kayaba long time ago
While I agree with you that in a real world situation, the government would find a way to free these people this is an anime about a virtual world. What is the fun if they escape through the help of the external world?
Ya, if the players were able to escape the game through external routes, the whole story would have ended after, say episode 1, and would have made the whole thing ‘boring’ (they might have been able to make a story where the incident is only just the beginning, but that would go in a whole different direction than what is shown now). That being said, I wanted to write this post to challenge Akihiko Kayaba’s statement of how the ONLY WAY to return is to finish the game.