I completely empathise with the OPs situation. Several years ago, I was buddied up with a guy from work on a two tank dive out of Riviera Beach, FL. We dived the Mitzpa on the first dive and made a float dive on the second. We discussed our dive plan before we made the first dive. When I entered the water directly behing him, the last I saw of him was his fins as he kicked to the wreck. I followed him, thinking I could keep up, but he never looked back for an ok sign nor did he ever look for me. I had seen him enter the wreck (the Mitzpa can be penetrated safely, or it could back then) so I followed. I never found him in the wreck so I exited, looked around the wreck for a bit and then went back up the line, made my safety stops and got back on the boat with 1500 lbs still in my tank. I was ticked off. When he got back on the boat (tanks near zero lbs), we had a long discussion. Since the next dive was a float dive (most people incorrectly call this a drift dive) and we were going with a group of 6, I thought things would be better. Nope, he hit the water kicking like a fool and we came up on him in about 20 minutes. He was kneeling on the bottom, and he showed me his guage, he had 500 lbs left. I took him to the float line and showed him the way to the surface. I finished my dive. And I never dived with him as a buddy again. Turns out no one wanted to be his buddy. Wonder why? So, the one choice on your poll, "Let the idiot go.", wasn't there. I couldn't vote.