What is the name of the scifi movie from the 90's?

I can't remember the name of this movie but here is the plot. A group of soldiers/mercenaries/criminals gets sent to some kind of base. It turns out one of them is an alien/super soldier that starts to take them out one by one...and it turns out the whole thing was just a test for this alien/super soldier. I know not really specific, the only other specific scene I remember is a black woman who was on the initial team gets her neck bite by this alien in a lab.