Perfect A&I topic. We have two sides to the story-- one in which the instructor held him under and physically prevented him from surfacing, and the other in which he merely communicated to the student that he shouldn't surface-- but both accounts agree that the instructor felt completing the safety stop was more important than getting to the surface where the student had already run out of air twice on a deep dive. Now this is something we can argue about, whether or not we ever get all the facts!
Personally, I respectfully disagree with your position. Given a diver who had already run out of air even once, even if I were sure there was plenty left for us to share, I would skip the safety stop. And in fact I have made exactly that decision in a real-world situation. My instabuddy and I had both just signaled to each other that we each had a little over 1,000 psi left at 70 feet and we were ready to ascend. As we began our ascent, she suddenly signaled that she was out of air and grabbed my octo. I helped her get the hose out of the D-ring and we ascended at a normal rate but with no safety stop. On the surface, her regulator started working again. We never did figure out for sure exactly what the problem was; she was using rental gear and was only here on vacation. I surfaced with plenty of air still; we could've done a safety stop, but I stand by my decision not to and would do the same again. Granted, 70 feet is not a deep dive, but I'd also do the same if we'd been deeper. And I always do safety stops absent a problem this serious, and I even do at least 5 minute stops on deep dives or dives where my NDL has gotten below 5 minutes.
But this is a great what-if to discuss!