Gitmo has a great gym as I have heard and the food is excellent, probably better than most on SNAP.
I think the flaw in the plan is you need to construct a shape charge that transfers the explosion forward into the target rather than exploding out and back. In the old days we called this a HEAT round.
It is a lot easier to make a functional exploding bullet than it is an exploding arrow. It might work better if you used the center core of a broadhead to carry the charge but you still need a way to detonate it after it begins to penetrate. The explosion has to take place in your target not on it.
The Bowmag still fires on impact and not after penetration. You need a way to delay the firing for a couple of milliseconds so the force is released inside the target not on the outside. It does have the advantage of a bullet to penetrate but the bullet will be moving only as fast as the arrow.
I can't imagine anything more destructive to tissue than a broad head. Adding a bullet to an arrow doesn't make sense to me and reminds me of the crap exotic 12 gauge ammo that is sold on the market. When I was working as a diver, we used bang sticks that had a .38 blank at the end that was quite effective against sharks and I also used it a few times to remove stubborn boat propellers. The bang stick only works under water because the water pressure acted like a chamber. A bullet at the end of an arrow without a chamber or barrel doesn’t seem like it would do much. A broad head makes a big hole and lets lots of blood out, you don’t survive that. Down here on the border I assisted the local sheriff’s deputy on a call to a domestic dispute between two neighbors and by the time we got there it was a homicide. One neighbor shot the other with a crossbow and the victim was DOA with a softball size hole cut in his gut and lots of blood on the ground. Mental note to myself, never got shot with an arrow.
I have used the BowMag. They are a novelty. I shot an 85 pound pig at 18 yards with one. I hit him between the eyes, and the .357 round went off, and took out his right eye. He was PISSED! A shot through the heart with my .45 put him down. The BowMag never cracked or penetrated the skull. That was from a compound bow with a 75 pound draw weight.
Some things you do because you can, not because they are effective or a smart thing to do. If you live long enough you think 2 or 3 time before doing something like this. No one got hurt I give him a A+ for his effort.