Forget about sharks, entanglement, gear failure etc. For some reason, the thing that strikes fear into my heart is REVERSE BLOCK. I've never encountered it and I don't know of anyone who has but just the idea of being trapped 5m below the surface with the choice of drowning or popping an ear drum frightens me.
Actually you do know someone, me! My sinuses reverse block from time to time. Had it happen on ascent from a 120 foot dive. Got to 50 feet and it felt like the roof of my mouth was going to explode. Nothing I did relieved the pain, I descended until it went away and slowly, ever so slowly ascended up the line. It wasn't clearing and I started doing the math, I'm 1.5 ata from the surface, the volume of air that's killing me now is going to double before I get to the surface. Conclusion: This is going to SUCK. I was actually watching the bottom of my mask waiting for it to fill with blood upon rupture of a sinus. Not a good time for sure. Luckily it just hurt like nobody's business and I was able to make the dive after lunch with no problems, the pain had resolved.
Ber :lilbunny: