Dr. Pfeffer tells Roo she has to drain fluid from a chest cavity to fix a collapsed lung. A collapsed lung occurs when air fills the space between the lung and chest wall. Roo needs to drain the air from the chest cavity, not fluid. Psychiatrists are graduates of medical school so Dr. Pfeffer would know that.
A nuclear bomb couldn't just go off because it's on fire. It requires a detonator to be triggered, and even then it would have a safety. Certainly a high level CIA operative trying to retrieve a nuclear weapon, and the owner of that weapon would know the basics of how it works. Yet both of them believe it can go off by burning, as do the all the operatives.