[Smokin' Joe]

If you recall, the second batch of bombers in London 'fizzled' instead of detonating. TATP has a short shelf life, so if this guy was working with an old batch, it may not have been as potent as originally intended.

My bet is that he was hooking up the power source (batteries) to the detonator and trigger and either got his wires crossed or flipped the wrong switch.

Most 'deadman' swittches for detonators are a normal closed configuration, release pressure and the circuit is complete (as opposed to a deadman switch on a subway train, which would open the circuit and stop the train). If he was wiring the thing and hooked the power up so that it was routed through the switch without maintaining pressure on the switch, he would suffer from premature jihadulation.

Whatever his motive, I am glad that he is the only one killed.

[R. Scott]

I guess I sometimes make the mistake of thinking logically – and assuming everyone else does it to. I would have tested the circuit a few times before heading out. I would have been thoroughly familiar with the whole package. Arming would have been accomplished with one switch.
But then again, I’m not usually considered a nut case either.