Tim Roth's character

And yet, you can read news accounts almost every day of situations where somebody failed to even attempt a defense, in real-life situations where you can't believe somebody wouldn't.

A lot of it has to do with weirdly inexplicable psychological tendencies. If you asked some of these guys what they would've done if somebody had told them beforehand that their wives, kids, etc. would be threatened like this, all or nearly all of them would've said they'd sacrifice their lives. But there's something about the reality of violence, and to some degree the escalation of it through successive levels of compliance, that paralyzes people. People who live normal lives aren't used to coping with it, and they always seem a step or two behind the perpetrator as things escalate. They fail to recognize quickly enough exactly where they are and what's going on, how extreme it is, so this kind of power relationship exists where they simply comply. Three out of four airplanes on 9-11 were taken over by hijackers without any apparent attempt by passengers to stop them. People let themselves be ordered into a car because a guy tells them to and threatens them from 10 feet away with a knife, even though it's absolutely clear to anybody who knows anything about these situations that your best chance by far is to run at that point (and throw your wallet or purse behind you), yell as loud as you can and attract as much attention as you can, because once you get into that car, it's probably over. And even if you do get stabbed or even shot in that situation, with people in the vicinity, you're likely to survive. (Not so likely to survive if you do get stabbed or shot in the middle of a dark field or the woods.) But people comply anyway. They allow the gunman to walk them right to the edge of the grave, or they allow the soldier to walk them to the place of execution.

In a slightly different situation, but with more or less the same mechanism, they end up in head-on accidents that could've been avoided easily by simply veering off the road -- but it takes the driver more than a couple of seconds to catch up with the idea that somebody is in his lane when he's not supposed to be. Plenty of time to avoid it if you don't have that delay, but people just don't catch up. People have conditioned themselves, or society has conditioned them, or both, to think that everything is going to stay between the lines, and the other guy's going to stay between his lines too. Part of the sociopath's game is to exploit this kind of powerful preconception in a way that keeps the sociopath always ahead of the ability of the victim to assess the situation accurately and respond appropriately.

It seems that adrenaline has almost mythical features... but fact is that it effects muscles, so busted knee is still busted, no matter what. The knee won't just start working again, because you stopped feeling the pain or became stronger due to adrenaline rush.