I think the documentary on the Blade Runner set goes into that dust-up with the crew. Scott made a comment in an interview about how the crews in the UK and US were different, how the UK crews were all "good morning, gov" or whatever, and the US crew got all ticked off and even made T shirts mocking that phrase.
Anyway, I think that scene was originally a replay of Hurt's scene in Alien, and it was rewritten to let them see the whatever-it-is before it attacked as opposed to it just being an instant attack. Besides, if you were a biologist, wouldn't you stare at a pale cobra with a vag for a mouth???
The Jedi Master