When a Grunt is ordered to move, "Why don't you go over there?" or "Uh, I don't think so!"
When a grunt sees his ally die, "Oh no!!! He owed me money!" "Oh no not again!" or if u want, Grunt runs* "I've already died twice in halo 3!"
when a grunt kills somebody, "It's called dodging, try it!" (also u can use it for the ally thing), "Grunt 1 stupid human 0!" or "Haha I win, but what do you care you're dead!"