SPOILER AHEAD!
When Charlie said "nothing happened" and "what, they haven’t come out yet" he wasn’t saying they were dead. He was saying nothing happened. The glow, the flash, the boom was all related to the emp and the hatch door flying through the air, which we assumed to be because a massive explosion happened, but in reality the pulse projected it.
What if the key was not a bomb but instead just another way to discharge the electromagnetic buildup?
Good point.
That’s exactly what Dean and I were saying!