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.
Sounds like the odds favor that. That was what the Brits did to the Brazilian mistaken for a terrorist. Two or three to the base of the skull.