Lots of why this and why that. That's one of the main problems with these videos. We have no idea of the circumstances at the time, only lots of maybe this or maybe that. Here's another maybe: the company 737 had a slot to meet and ATC asked the 757 to expedite vacating the runway after landing. Note that I don't mean ATC specified he try for that taxiway. That part would have been at the Captain's own initiative.