As the other commenter explained, you absolutely need to do decompression for long-enough dives. The limit at 19m might be a few hours so it doesn't affect recr

As the other commenter explained, you absolutely need to do decompression for long-enough dives. The limit at 19m might be a few hours so it doesn't affect recreational diving, but in this case they exceed it. So if they had scuba gear they would have to stay at 19m and wait for help.