She won't find any argument from him here. "Agreed. If something happened to the ship, it might not be safe on the other side, so don't go through on your own, either." Jim is fairly certain he doesn't need to worry about that with her, but it never hurts to make sure before the unexpected occurs. Radiation poisoning is a horrible way to die, and he knows that far better than he'd like. Warp core breach, exposure to vacuum, even just plain old ordinary fire... there could be any number of hazards on the other side of the door.