Eyeballing from the video it looks like he turned 70 degrees off center line and stopped, then backed up unnecessarily.
Had he turned 45 degrees off center line towards the right runway edge, he could easily made a 180 turn, safely.
But for you naysayers, and techies:
http://www.boeing.com/assets/pdf/com...aps/757_23.pdf
Section 4.3, page 73. 757-200, R3 (nose gear).
I may be reading it wrong (forgive me) but it looks like the 757 needs 71 feet or 21.6 meters to do a 180.