Courtney.
The weapon would have two mechanisms within the fuse, the rotary one being an interlock for the second - both required for detonation. What the chap was saying was that the rotary one had done its job (i.e. had been dropped at sufficient speed for the vane to rotate the correct amount of times at the correct rate).
The other section of the fuse would have a timing delay, triggered at release, after which it would need to sense the deceleration of a hit. Drop from too low and weapon hits, then arms, no deceleration, no explosion.
So he was right. It was sat there waiting to hit something, unaware that it already had. (Not that I suspect bombs can muse to themselves!)