Every time I watch military diving videos such as these, I'm reminded of my PDIC open water course in 1981. Many of the same concepts were taught, but in a slightly less aggressive way of course.
But, to compare:
1. Attitude
Like these special forces instructors, our instructors were no nonsense. Yes, they were friendly, but at the same time distant and professional. To be a certified scuba diver was something to which you needed to aspire. The instructors didn't try to sell you on the idea of becoming a diver. You had to sell them on the idea that you deserved to be a certified open water diver. You needed to show up when and where you were told. Tardiness was unacceptable. You needed to listen well and follow instructions. They set the bar. You met it. No one was coddled. You either passed or you didn't.
2. Physical Exercise
Every class began with lap swimming and snorkel swims. We were expected to swim and snorkel hard to develop our fitness and improve our kicking techniques and muscle endurance. We were timed and encouraged to do more and work harder and faster. A weak kick or any inefficient or incorrect kick was a "No Go" for open water. A student needed to prove he or she was a strong swimmer. Unlike the military trainees in the video clip any use of hand sculling was also a "No Go." You either could use your legs like a diver or you couldn't be a diver.
3. Comfort in the Water
We had to perform underwater swims, drown-proofing exercises such as bobbing and jellyfish float, and all skills had to be performed without touching the pool. No hanging on the pool deck. No using the bottom for help. You could flip-turn off the walls when swimming and some skills would start while kneeling on the bottom, but once the bottom was removed from the equation we couldn't touch the bottom. For example, the first time you flipped a tank over your head to don it in the water you could use the bottom in the shallows. After that, you needed to don the tank in deep water without help at the start of every class after you completed your laps. Once you removed and replaced the tank kneeling underwater, you needed to do it while hovering afterward. You were strongly reprimanded for touching the pool sides or being on the bottom. Enough violations and you failed. A typical class/pool session was 1.5 hours in class and 1.5 hours in pool once a week for 6 - 8 weeks before open water.
4. Failures & Harassment
Things would go wrong. We'd either make mistakes as students, the instructors would create them or the equipment would misbehave on its own. We had to problem-solve underwater. Our masks would be snatched. Our regulators would be pulled from our mouths unexpectedly. As we became better at dealing with problems and as our skills became better, we were dealt combination and multiple failures to solve. You'd be replacing your tank underwater when suddenly your buddy would be out of air and no sooner did you fix that then you'd lose a mask.
As one of the special forces instructors remarked in the clip, "Nothing out here is done with the intention of smoking the student unnecessarily. Everything is done to make him a better diver."
We understood that we needed to perform correctly under stress and we had to train out certain automatic survival instincts and replace those with trained behaviors since water was as unforgiving as its properties and physics. However, we weren't hit hard like football players. The worst would be a very hard tap to simulate a scared diver desperately trying to gain attention and air in an OOA situation or having a reg ripped from our mouths and needing to calm the victim and retrieve it to begin buddy breathing. Everything that we overcame created confidence. Like the clips, some people just didn't have the comfort and abilities in the opinions of our instructors to handle what the oceans, lakes, and rivers of the world could throw at us.
To emerge a certified diver was one of the proudest of accomplishments.