I'm one training short of hypoxic trimix (after a regular trimix course). I think you seriously over-estimate the complexity: open-water course is 3 days, advanced open-water is 2 days, nitrox is ... half a day?, basic tech diving (advanced nitrox + decompression procedures) is 7 days (50-100 dives minimum iirc), trimix is another 7 to 10 days.
Loads of people I know did all that without any difficulty and without leaving their day job. They weren't in the navy either.
The most advanced thing that I see here is how do you trigger the explosion underwater, plus of course getting the explosives somewhere.