I get that, but my point stands that while you're forced to be very close to them, you're not forced to talk to them. You could even make up an excuse for not wanting to talk. For example, "Sorry, I don't want to chat right now, I'm going to try to take a nap" or "Sorry, I don't want to chat right now, I'm going to put my headphones on & listen to some music". This isn't Clockwork Orange where he's forcing your eyelids open.
Making up excuses in such a situation is widely seen as rude. If you tell them something like "I'm going to try to take a nap," and do not proceed to take a nap, or at least fake one, you're liable to give offense.
In a situation like this, I would very likely be taking the time to think, and telling someone that you want to think instead of talk to them is widely viewed as rude because it privileges your thoughts over their company.
r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.