The gent or missus in the LHS knew exactly what he or she was doing....
Surely someone who knew exactly what they were doing would have used the turning circle at the end, not risked a burst tyre shortening the landing roll out, not risked going over the hard pan edge, not embarked on a risky manoeuvre that could have blocked the runway for a long time, not induced brake calling issues.
The ATC "expedite' issue is a red herring. B757 rolls out, goes to turning circle, makes 180, back tracks rwy and vacates. B737 enters rwy, back tracks, goes to turning circle, makes 180 and holds. Difference in time? Nano seconds.
I wonder what the conversation was like in the cockpit afterwards. I suspect the F/O was asking some questions.
I suspect there will be many on here who will have to agree to disagree. IMHO this was a risky attempt to make a turn off, unnecessarily. There was doubt, and when there's doubt there is no doubt.