That cable wrapped around the cutterhead" - that's the part that gets me. How deep was it actually buried in the silt before you hit it? I've seen sonar miss stuff that's sitting just under the mud line. Makes you wonder how many more of those cables are down there. Your torch and grinder plan sounds rough. Did you have to worry about the cable snapping back while you were cutting? I've heard stories of guys getting hurt bad when tension releases unexpectedly.

Is this one of those new builds where they crammed the conduit in after everything else was already laid out? I've seen that way too often in the valley. They pour the slab, frame the walls, then somebody realizes they need to run electrical. So they just hack channels into the concrete or shove EMT through studs at weird angles. It screams rookie oversight or rushing for permits. Either way, you're going to have fun fishing wire through that mess later, or paying someone triple to do it. Phoenix heat makes that concrete a pain too, so any botched conduit is just asking for expansion issues down the line.