Years ago, I instructed two students to stay close to the reef throughout the whole dive. During the dive, the girl stayed close but her boyfriend was diving 3m away from the reef. Despite repeated signals to swim closer, he failed to follow instructions.
When I saw him struggling when the current grabbed him, I decided to grab the tank of the other diver, swam to him and grabbed his tank as well.
We surfaced roughly 5 minutes later. The boat was far away, too far to swim. Waving my SMB resulted in the boat acknowledging my signal.
So, what got us in that mess?
- The student repeatedly failed to follow instructions.
At that moment, telling him that was pretty useless. Instead I kept telling him repeatedly to hold the SMB line.
Had the guy drifted off, it would have been clear why. You can try to pin liability and responsibility on instructors, but when divers fail to follow instructions, it ends.