In the underwater scenes Jaime and the other divers are heard talking as if by radio, however when their faces are shown, their mouths are wrapped firmly around the scuba breathing apparatus. They definitely would not be able to talk.
Jaime and the other divers are supposed to be over 250 feet down. Although there are lights on the PTC, the underwater scenes seem to be lit by sunlight. No light could penetrate that deep into the ocean, so they're obviously diving in much shallower waters.
In the first underwater sequence, we are, once again, presented with a "magic camera" that shows us numerous angles, one after the other, with no hint of having repositioned itself.
Oscar: Here's the setup. Somebody is trying to prevent us from testing our new submarine detector device. One of the divers quit this morning because of so-called 'accidents,' and the other two are about to. Jaime, you're going to be diving in several hundred feet of water. You're going to have to be checked out on your safety techniques. We've got to get thoese devices planted and checked—it's very important to us. And besides, if you, a beautiful, frail young woman is ready to go down there after what's happened, I'm counting on the men's macho to keep them from backing out.
Jaime: I thought... uh... chauvanism was a thing of the past.
Bruce Shurley directed the underwater sequences.