True - Dr. Stutz did not see Watson turn her air on or off. But what he may have witnessed is that Tina was being deprived of air at the time he saw Watson holding her in a bear hug. Dr. Stutz did see Tina's arms and legs twitching as she sank to the bottom, indicative of asphyxiation. She was in the process of dying on the way down, even though her air was on. You continue to state that she had to be completely dead before Watson let her go, but I don't think that is the case. All he had to do was incapacitate her and it only takes a moment to get water into the lungs.
If I said she had to be completely dead, then I was being careless. If she was incapacitated, that would be adequate.
Whether he quickly removed her reg and replaced it, or turned off her air, doesn't matter.
I started out to say that I must respectfully disagree and that unless the prosecution offers a single explanation with evidence, a jury may might not convict. I was going to continue that in most jurisdictions the jury does not need to agree on every detail, i.e. whether he quickly removed her reg and replaced it or turned her air off and then back on, so long as it agrees he did one or the other. And, I was going to say that nonetheless, a jury might have a problem with Watson having killed Tina unless the prosecution could offer a single explanation.
However, as I typed that, I realized it might not be so problematic for the prosecution. It could simply take the approach of saying Watson killed Tina by getting her to ingest seawater but that is unclear exactly how he did it. It could then offer different means by which he could have done that.
The problem remains that in the absence of someone who could say they saw what it was that Watson did to cause Tina to ingest water, the jury may have a reasonable doubt that he did anything. After all, there are reasons other than having one's air turned off or having the reg pulled from one's mouth that lead to the ingestion of water and death. Defense experts would certainly testify to that. And, I would think that even the prosecution experts would have to concede it.
What Dr. Stutz did see was that Watson had her in his grasp, let her go, she drifted down, completely helpless and Watson swam away. He did not see Tina knock Watson's mask off. He did not see Watson adjust his mask. He did not see Watson kick down for Tina. I think it will come down to who the jury will believe what happened at this moment. Will they believe Watson? Or will they believe Dr. Stutz? They both can't be telling the truth. To me, that is the ultimate question yet to be decided.
I do not think this is the ultimate question. I also think that Dr. Stutz will be the more believable witness. Based on what I currently know from public information, I'm not sure I would believe Watson about anything relative to that dive.
But, in the courtroom, it might not be bad for Watson if he is not believed about anything. In fact, it might lead the jury to conclude that he was so rattled by Tina's death that everything he said must be discounted, and discounted to the point that there is nothing to be contradicted. I've seen it happen. Beyond that, a jury might conclude that the reason he was so rattled was because Tina's death was truly a horrible accident.
As far as "ultimate" questions, since I think Dr. Stutz' testimony might exonerate Watson, i.e. negate his having turned Tina's air off or removed her reg, credibility is far from the ultimate question.
Apparently, you have not taken the rescue course because I can tell you, it does teach you how to "rescue" another person. That is why they call it a "Rescue Course."
I have taken the rescue course. I was taught how to rescue another person. But, just because you and I were taught how to rescue someone, that does not mean Watson was. I find it hard to believe he wasn't taught how to rescue someone. But, I wasn't there, so I can't be sure of what he was or wasn't taught. (See "Schrodinger's Cat.)
Moreover, even if Watson was taught how to rescue someone and was able to demonstrate the skill during the class, that does not mean he could do so at the time of Tina's death. Nor does it mean he recalls having been taught how to do it. For example, I know that I took statistics in college and that I passed the class. However, I do not recall having been taught what standard deviation means or what it does. (Note: Despite the fact I don't recall it, if I were a betting man, I'd bet I was and simply do not recall having been taught it.)
Well, I do believe that the defense will have to change some of their strategies that they have released to the public and I believe that is all part of the deal here. But just to make sure that another rumor isn't started, they have not proclaimed that Dr. Stutz saw the DM drop Tina - at least not yet. It's not going help if Wade Singleton, the rescue diver, does not corroborate it. I'm sure he would remember if he dropped Tina and swam away from her.
What lawyers say in television and newspaper interviews is often just distractions. The more things that the other side must prepare to address, the more likely there will be something it fails to address and that could be the difference between a conviction and an acquittal.