I don't see much difference between combat boots and rock boots. I did a cave dive once with deck shoes. I hung my booties out to dry and forgot to collect them the next AM and had to dive with the shoes I was wearing. I'm sure I looked stupid, but it was that or not dive. Fortunately, it was an easy dive without much swimming, kinda sloshy and squeeky on the way home too. I also did a dive once without a wing when I forgot that. And, many, many years ago, I even dove once with a piece of rope tied around the neck of a tank when there weren't enough BCs for everyone to get in the water. And, when I worked on the Abyss, I made a set of doubles with duct tape. Anybody can dive with a full set of gear, but the real challenge is how do you handle an out-of-gear situation, LOL.