I continue to be amazed by what some folks think refs, or assistant refs, should or should not do.
In a potentially dangerous situation, at most the assistant ref would be informing the ref to watch the joint. The assistant ref would not have the ability to stop the match, even if they felt either wrestler was in a potentially dangerous situation.
From the rule book:
7.6 Assistant Referee
In tournament competition, it is recommended that one assistant referee be assigned The use of an assistant referee is designed to minimize human error
The assistant referee will be granted the same mobility as the referee; however, the referee will be in control of the match. (this bold is added by me, for emphasis)
Assistant referees must aggressively take part in the officiating of each match.
When possible, the assistant referee should be in a position to observe mat action and the clock simultaneously at the expiration of each period if a towel tapper is not used.
7.7 Assistant-Referee Procedures
7.7.1 Verbal Communication. Verbal communication between the assistant referee and referee is encouraged.
7.7.2 thru 7.7.8 also deal with the Assistant Referee, but don't indicate anything about the assistant ref making calls, stopping action, etc. Quite simply, that's not the role of the assistant ref.