[Cboldt]

At first, my thought was "how do you know what sort of trigger is on the bomb?" Meaning, "How can you be so sure there is no deadman switch?" But on second thought, an active shooter would not be able to maintain a deadman.

That still leaves a question of how easy, quick the trigger is; and also the possibility of a "heartbeat" type of switch, where if the switch doesn't get attention each minute (or whatever interval), the fuse is lit.

[Travis McGee]

Electric switches with batteries have almost zero chance of getting past a metal detector, not that that would apply in this case. But the soda-can bomb on the Russian plane also had a friction-type fuse detonator, as did the shoe bomb etc.

The rolling into position and giving a long yank followed by a 2-second delay tells me it was a friction-fuse device.

No way to know in advance, of course, but if you have a chance for a head shot, TAKE IT.