Here's a list of the few people you don't need to kill
The Allies
Name
Description
Picture
Scientists
These are very useful for opening security doors and giving you
information.
Security Guards (AKA: Barneys)
Security Guards are the only people on your side that have
weapons - they can help you through some nasty fixes. They can also
open security doors for you, although I thought that would be
obvious.
The G-Man (AKA: The Man in the Blue Suit)
Not much is known about this guy, but you see him quite a lot in
the game. He doesn't hurt you, so I suppose he's an ally.