One of the "intangible" type skills we try to impart to the candidate divemasters is to be ready to deal with situations that are unusual or that they have not encountered before. The thinking is that there will be times that you have to deal with unusual challenges - both in-water and on the surface. We try to prepare the candidates to be ready to think on their feet to be able to deal with a wide variety of equipment problems, and problems that divers might have etc.
One of the candidate divemasters was faced with an equipment problem that took me by surprise. We were in the deep end of the pool and the candidates were being evaluated on the various skills that they have to perform (up to demonstration quality), The particular skill that the candidates were working on was the scuba unit remove and replace.
The last candidate went through the paces to remove his scuba unit, and when he had the scuba unit in front of him, I noticed that something looked strange and I could not quite understand what I was seeing. He had the mouthpiece of the second stage in his mouth, but the second stage was laying on the floor of the pool. Somehow the mouthpiece became detached from the second stage. The thing was that I was so focused on evaluating his performance of the skill that I could not immediately figure out what the heck was going on with the black thing in his mouth!
The most surprising thing was that he sat there totally calm and confident going through the paces of starting to replace his scuba unit. Almost at the same moment the course director (CD) and I realized what was happening and raced over to the candidate to assist him in case he panicked and shot to the surface. Incidentally we teach our students to solve problems underwater and not to bolt to the surface immediately when faced with challenges. The candidate was remarkably calm under the circumstances and did not panic or bolt to the surface. He calmly spat out the mouthpiece, took CD's alternate airsource and completed the skill.
CD and I were very impressed!
Once the candidate had repaired his equipment, he performed the skill again and scored very well. CD said that he had seen this kind of thing before, but I must admit I have never seen a mouthpiece detach from the the second stage underwater.