I think it’s more to do with the ‘power’ of the club doc in that situation - the Cats doctor tried to get him to leave the ground 3 times - he literally did what he could to get him off the ground for a proper assessment.
The doc should either have the power to notify the umpire immediately ala a blood rule type situation or have the ability within the club to act as a runner basically and say ‘Cameron - you’re off’.
Tough call - would be interesting to see if the clubs supported either scenario.
Has to be an independent doctor IMO, club doctors do their best but in the end they are part of (and usually a big supporter) of a club that exists to win games.