
Maybe, it's that the Jaffar sound is playing, so is_guard_fighting = 0; so once striked, he is dead, similar to trick 94 on PoPOT.
Also, when Jaffar is dead, the level exit door just gets opened. If there's no level exit door on room 3, 2nd floor, 4th tile, sound of opening the door is not played, but it is open, so you can go through any other door as discovered before.
