What will usually happen is that an enemy Viper will enter his aggro range and he'll turn and run towards them. This brings him closer to the nearby base, and so once he gets going he usually won't stop until he's cleaned the place out. This is hilarious to see, although it's really, really annoying if you're trying to turn in a quest and he runs off. You end up chasing him all over the place, frantically clicking on him and trying to activate the next mission so you can get on with things.
That is beautiful. "Excuse me? Mr. Scientist? Could you stop killing bad guys with your bare hands long enough to tell me what you want me to do because you're just a weakling scientist?"
Hey there. Do you remember a few seconds ago how this room was full of your friends and not dead bodies? Are you positive you want to keep fighting? Yes? You do want more fight? Okay then. Hold still. This might sting so bad that you die.
I wish I had somewhere to use that last line! (This update's been golden straight through. Good show!) Though I do admit to uttering something similar (in ANY game) to the whole rant whenever a lone guy charged through a pile of his dead and better-armed comrades in the vain hope that he might be able to do what they could not. I usually kill those last stragglers slowly, just to give them false hope.
I'd be a lousy superhero.