chief would probally scatch his head with the knife and then realize he just cut the side of his head open or when he's running at them he falls and the knife slips and he stabs himself
travis is just kinda...well to similar to the chief, todd is kinda neutral its almost like he sits there "I dont want to harm you, so I wont" and cortana makes it relativley better but she just has the same "judgemental" attitude as the arbiter did...so I say SLICE SLICE SLCIE!!!!!!!!
Chief could just have them put in a box and send away by UPS to Antartica or somewere far away, That way they could be gone from the series but "could" come back in the future... Being really pissed of at Chief.