I don't see much difference between
1. Aliens being choked by Wolf, flailing about frantically
2. Celtic slowly strolling over to Grid and then striking a pose before being pounced
You guys are trying to draw the distinction that 1 is out of character but 2 is in character. I say we don't know whether 1 is in or out of character because we've never seen how aliens react to choking. We only see it this one time.
As has been mentioned, an alien does walk into a spear in AvP. It would appear that alien silliness isn't limited to Requiem
Ehhh... the biggest difference between arrogance and stupidity is whether or not one actually survives the experience.
There IS a line between arrogance and stupidity.
If Mike Tyson dismisses me with such contempt that I manage to KO him with a lucky punch, that's him being arrogant
If I manage to daze Mike Tyson with a lucky punch but decide not to follow up immediately, that's me being stupid.
City Hunter is standing over a weak little human, apparenly wounded and helpless. Would it be idiotic for him to assume that the fight's over? Not really.
Celtic has just experienced the potency of alien acid. He knows that the net cuts, he knows that the acid corrodes. Would it be idiotic for him to assume the alien is contained? I would say yes.