The Slowness of Consciousness

Sudden disappearance of consciousness with no bad feelings or fear probably happens with victims of pyroclastic flow from volcanoes. If that comes without warning, nuclear blasts have a series of events. These all happen at the speed of light. So if you see a bomb descending and you realize you're going to be quite close to the point-blank detonation, there's actually no reason to panic. Just like the drivers who never witness the airbags deploy, you won't witness the bomb burst.