Just thought of something funny about Bishop

Re-watched Aliens earlier and realized Bishop assures Ripley

"It is impossible for me to harm or by omission of action, allow to be harmed, a human being."

Lol, yet he says this right after he risked stabbing a human being in the hand! And I mean, it was a risk, because Bishop's aim wasn't perfect since he accidentally stuck himself!

Lol, can you really blame Ripley for not trusting him? What gives, Bishop!?