It's like a math equation. If (Y = Potential danger, X = stupidity of unit Red Shirt) = Speed and traumatic nature of Death of all but 1 person. Usually a woman who was smart enough to avoid the idiots or learn from their mistakes faster then anyone else.
I don't know what they are panicking about. I mean if that floaty device lets that thing out they shouldn't worry, the creature CLEARLY looks friendly....with it's Predator hair and deadly crab legs of doom.