In the room where harry enters and stumble back after the floor gives out in front of him you can skip pushing the box. To the left of the door is an ston archway in the wall. Line yourself up so that when you jump at it you slide across it and grab the ledge on the other side.
(note this is a particularly difficult trick and saves very little time if failed.) (not tested on the ps2 or xbox versions) (I do this in my run, It happens at around 17:20)