There’s no substitute for situational awareness.
The three yuts obviously rehearsed this attack. The video shows a high degree of coordination.
There's little he could have done about suddenly being headlocked from behind except spray the perp with gas (which might also have gotten on his own clothing) and light a match. Unless he was packing; but the perp might also have put a gun in his back, or said he had done so, while choking him.
Can anyone on here recommend a course of action, based on the video? Asking for a little old lady who fills up after church twice a month.