Brad, Jessie, Isabella, and Otis all count as survivors for this achievement. Using this method you must lead 48 survivors to the Security Room. This method aims for Ending B which means you're going to let Case 7-1 lapse intentionally on Day 3 and then be at the Heliport at noon on Day 4, September 22nd. I've verified that this method works on the Xbox One re-mastered version if you're going for the Saint Achievement exclusively.
