-In Uplift Reserve, grab the Warthog at the start of the level and load up with Marines. Shots fired from the Marines do not count, and you cannot use the e-brake or horn. Simply fly through the level.
-This achievement requires you to complete any mission under the Legendary difficulty setting with no shots fired. E-braking or honking the horn with the Warthog also counts against you. Most players just pile a group of Marines into a Warthog and let them do all the shooting. The following method works slightly faster and is also easier. When you get around the first corner from the starting point, there is a small battle going on with a Wraith and a few smaller Covenant vehicles firing on a few UNSC forces. Steal a Ghost from that area and boost all the way to the end of the level. The boost on the Ghost does not count as firing a shot. If your Ghost is getting trashed, grab the one on the other end of the bridge you cross as the Space Elevator collapses. Also, you can climb the hill just after this location using the boost feature, instead of going along the path and getting shot at by the two Shade emplacements.