I'm surprised that call 911 hasn't come up yet.
I also didnt see why every man in there just didnt jump on the guy at the same time. Strength in numbers.
The situation is probably evaluated by the individual at the time in terms of me vs him, not us vs him. I would not jump in just hoping others would follow suit.
Given the basic description of the space and amount of people, it would be difficult to state a course of action beyond calling 911.