My boyfriend and I just got back from a dive trip, where we 'negotiated' with the DMs a bit. My boyfriend has only been diving a couple of months (6-8 dives). The first dive we did, they were taking us to the wreck of a small boat, in about 20m of water. The plan was to swim in the stern hatch, through the boat, then out the front. I wasn't totally happy with the idea, especially when the guide said the wreck was full of silt. When we got to the hatch, the guide turned to the group, and pointed in. My boyfriend shook his head 'no'. They guide motioned that he (my bf) and I should swim round the outside of the boat to the bow. The rest of the group went in, and we met up with them again at the other end.
Another time, we were swimming along the top of the reef at 20m, then we went over the edge, where the bottom was 90m. I didn't like that, so I just waited at the top with my boyfriend. When the guide turned to check on us, he saw that we didn't want to come down, so he came back up. We were the only ones on that dive. Another dive where the guide went deeper than I wanted, I signalled to my boyfriend/buddy to level off, and we swam along about 7m above the group. We had 20m+ viz, so it was easy to keep track of them.