Is it a conundrum? As a fighter, you do not get paid to do the referee's job. To me that's pretty black and white.
Also, if you let him recover and have to hit him another hundred or so times to get the win, you're probably doing more damage than if you had simply kept going and put him away in the first place. It's far from a guarantee that self-refereeing is doing the least minimum of injury necessary to win, and then take into account additional damage you yourself might sustain should you allow the fight to go on.
If we want the sport to be safer the best thing we can do is take the gloves away - those things do nothing to protect the person being punched, they only protect the puncher's hands which enables him to tee off full-tilt. Before gloves, the prospect of MMA fighters fearing brain damage seemed laughable. Now it's on pace to possibly overtake boxing as the worst sport for your brain.