Originally Posted by
_L_
It's at 9:54... but, as I said, you will only encounter it if you enter that screen from the north, which is the normal gameplay sequence.
That screen (9:54) is the only path to the far side of 9:64 without directly launching oneself across the broken bridge there. Thus, if you enter 9:54 from the south, then the game realises that you've broken sequence, and removes the scripted encounter.
Incidentally, I will certainly be adding several more save points to this and other areas, by popular demand.