You are all on the right track. The main point is the surface interval was not long enough and the safety stop on the second dive was not long enough.
I gave the basic information because that is all that is needed to know the above information. Dive conditions such as temp, current, fresh water or slat water. If you where taking an basic/advanced scuba class you would get very simular question with the same kind of information. You would then be asked what the diver should have done differently. The answer should be, longer surface interval, shallower second dive and a longer safety stop on the second dive. You don't need any more information to know that. If the diver was using nitrox or a mixed gas, that would change the whole situation. Nitrox and mixed gas are not taught in basic/advanced open water scuba classes. Compressed air was used.
I just got back from Aruba. These two dives where planned by the dive boat. On the first dive we ( the group ) started to surface. No one that I could tell was or had done a safety stop. The dive leader gave everyone the thumbs up to surface and then surfaced. I noticed 3 other divers go to the current line, my dive buddy and I followed. As other dives slowly went up the line, my buddy signaled me that his computer was telling him to do a safety stop. His computer was set for a safety stop at 20 feet, mine was set to 15. I stopped at 20 feet, We compared computers and hung out for about 3 mins. We surfaced and where the last ones on the boat. No big deal. While doing our surface interval, we were given a briefing on the second dive. It was planed for 45 to 60 feet. Important note, the second dive was only supposed to be to a max of 60 feet. I went 12 feet past the plan. I knew I did this and planned to lengthen my safety stop. Not a problem, or so I thought. I stayed with my dive buddy and the group the whole dive. There were two times when the dive leader had disappeared. I could see everyone except the dive leader. I noticed most divers looking around like they where lost. Both times I was able to swim in the same direction we had been going and find the dive leader. Both time he was just swimming along just assuming everyone was behind him. Visibility was about 35 feet.
When the dive was over I was surprised to see that the dive leader was giving everyone the thumbs up and wanted everyone out of the water. I thought to myself, what about our safety stop. I checked my computer, which was telling me a max depth of 72 feet. My nitrogen gauge was one bubble from decompression. Clearly I needed a safety stop. I signaled my dive buddy. His computer was beeping and telling him the same thing. He had stayed about 5 to 10 feet above me the whole dive. He gave me the level of signal and pointed to 5 mins on his computer. I gave him the OK signal. Within just a matter of seconds I could hear the dive leader blowing his little noise maker and wave both hands at us. I pointed to my computer and gave him the level off signal. He angerly gave me two thumbs up. I repeated my signals. Which just made him more anger. I looked at my buddy, who gave me a I am confused signal. I gave him the thumbs up and he returned with OK. When we got to the surface, the dive leader started yelling at me about how I better get out of the water when he tells me too. I told him I needed a safety stop and so did my buddy. My buddy then pulled his computer out of the water and said " see look, can't you hear it beeping". The dive leaders response was I don't need a safety stop, why do you think you do. It is important to note that before this dive, during the briefing, he told everyone, "when I give you the signal to get out of the water you need to do it then, don't be pretending to look at your computer and ignore me." I couldn't believe he said that but didn't care. This went on for about 3 mins on the surface. He started cussing at me and telling me I didn't know what I was talking about. I called the dive shop when I got back and told them that I would not be back the following day. I talked to the owner who said my dive profile is my responsibility, but for some reason he didn't believe me that I was told that I didn't need a safety. He didn't think his dive boat employees wold say anything like that. So he says he will talk to them and get back with me. I get a message later that night , that says, " I am returning the call like I said I would, I want to know when I can come by and drop of your t-shirt and membership card. Please call me back." LOL
Here is an interesting note. My dive buddy was a guy I was paired up with when I got to the boat. He was a nice guy, but lack some knowledge about diving. When my dive buddy and I got back on the boat after the second dive, he came over to me and asked, " So what will happen if we get the decompression sickness? Will we just get a bad headache? I rented my computer so I am not sure if it is working right. It says error now." I told him mine is working and we should have made a safety stop. I was dumbfounded on anything else to say.
I know a lot of you are going to telling me how bad I was for going 12 feet deeper than the dive plan. But do this, look at the PADI dive tables. If I would have stayed at 60 feet instead of 72, I would still need a safety stop. It really doesn't matter how deep or how long I was down. Every dive should be ended with a safety stop at the very least.
There are several other interesting things that were done and said on this boat. Here's a good one. " I have been to 380 feet with compressed gas. I don't need that mixed gas stuff." " I have been diving since I was six years old". These are comments made by one of the dive leaders
I didn't know anyone could get certified at 6 years old.
Let the floggings begin. I'm still alive and have the use of all my limbs so I guess I am good.
