Ok I'll just give it to you that you can drop your weights faster than I can turn on the valve... You quite possibly in fact are right.. you take 2 - 3 seconds to drop the weights (assuming they don't snag on something, leg, bcd, fin whatever, and that your not horizontal.. if your horizontal then you have to roll to one side or go vertical to drop it all the way off..) let's leave it at 2 - 3 seconds.
It may take me 3 - 4 seconds to turn my valve on in a pinch if something doesn't go right about the same as dropping weights if all goes well. But lets leave it at 3 - 4 seconds
I assume we are still talking about the same scenarios that this debate began with..
1) Diver not ready to enter water, kit on, air off, falls in water
2) Diver thinking he's ready jumps in water with air off.
What do you do.
A) Drop weights and go to the surface. Have someone go retrieve weights. put weights back in/on go on dive. (That assumes you can find them) How much of a hassle is it to put belt back on or reinstall into integrated pocket system (shouldn't be a great big deal but it's a bit of a hassle). This whole process might take only 10 minutes but has potential to take a lot more time.
B) Turn on valve and continue dive. Whole process takes only the amount of time it takes to turn the valves on.
If the tank is empty as someone threw out,... well we can still dump weights and we would have wasted about 5 maybe 10 seconds if things got fouled up.
It really doesn't matter how we slice it, what the situation is. If we enter the water with our valve off, the easiest remedy that makes the most sense will always be to simply turn our air on. I would imagine that there 'could' be some strange exception though I am at a loss to think of one.
If our rig doesn't allow us to do this it is a simple, most likely minor adjustment that will remedy this. Unless we have flexibility issues which we should work to resolve. All of this is simple stuff.
If our mask floods at 15' on our descent would we just pop up to the surface to clear it because after all we just descended?... No we'd clear it where we are.. The first thing we try to instill in new divers is that problems that occur under water should be remedied underwater.. simple stuff.
