With 2 dives and 4 regulators on the team, it takes 3 failures to reduce the whole team down to 1 regulator -- and even then there&#x27;s ways to survive and get out of the cave.<p>So more like 100^3 to start with, and then the failure rate in practice is lower than that (I&#x27;ve done 200 cave dives and I&#x27;ve had 1 failure -- and I know many other cave divers with similar levels of experience that have had none).