Your situation is not one I've personally encountered. But, I don't understand why anyone suspects pipe damage extends under the deck. If the pool room exploded, maybe, but probably not. If the PIPING exploded, then I'd be concerned.

Also, there is -- at least in the USA -- no such category as "pool specialist". I'm guessing that's also true in Canada. So I'm not sure what you mean when you use that term.

Why don't you just excavate the pipes, a few feet away from the pump room, expose and cut them, and see if there's the slightest evidence of damage extending underground. If there's none -- which is what I'd expect without an actual EXPLOSION -- then I wouldn't worry about it. However, if you want to go further, you can flush the lines into the pool, and then pressure test them.