This second half of season 5 is filled with insane ideas from Jack – unfortunately because he/they are put into insane circumstances. The insane circumstance that we left off with last week was the nerve gas attack on CTU, which led to the death of many CTU agents, including Edgar. It also led to Jack and several others getting locked in a few air-tight rooms. The new problem is that the nerve gas was laced with an acid that was deteriorating the seals of these safe rooms.