This might crop up elsewhere for others.
Every single time I die and the game tries to load the previous checkpoint, the screen goes black and locks up the xbox. I even tried restarting the level - same result. As I can't pull up the dash either, I'm forced to manually power off the xbox each time, which I'm not really keen on, as I'm afraid something will break eventually. Any solutions? :/
EDIT: Cleared the cache and went to the mission select menu. Previously it skipped the whole elevator to the lower deck sequence and went straight to the walker and the warship. That might have been the cause.