The WSB-TV News here in Atlanta isn’t much clearer, but my expectation is that the tug hit the jetway and caused an employee to fall from there, either through the opening that connects to the airplane or from the external stairway that allows employees access to the ground from the jetway.
Possibly but "a report from the Ninth Circuit Medical Examiner’s Office determined Friday that the ...man who worked for the airline died of multiple blunt impact injuries".
https://www.msn.com/en-us/news/us/orlando-international-airport-staff-member-dies-officials-say/ar-AA22GL8O
Multiple blunt impact injuries (versus falling) could be from a rollover.
Drivers roll them more frequently than outsiders would expect. A physically fit driver might jump clear but a crushed leg and pelvis was common.