Alright let's lunch some numbers, people are saying that Gally could kill chief easily. However in Reach, keep in mind this is a weaker generation of Spartans, a simple armor lock stopped noble 6 and I believe 5 from dying, Considering it was a chopper crash and from how high up I'd say armor lock would take down everything in Destiny. Bear in mind this is only Noble 6, a person who is WEAKER than chief