I'd like to turn a negative to a positve, how do you think the random characters are surviving in One Piece. Sure, we all must know about that "people with dreams don't die thing" (and that might be it…) but I have one theory, at least, for the big one: Pell.
After the explosion, Bird-form Pell is fighting straight up. Now, bird are light right? They have hollow bones and and feather help keep wind under their bodies. I think, the since Pell was flying up, the force of the explosion pushed Pell "up," like a wind erupting from under his wings. This would have "softened" the damage.
Now, from this point on Pell is several miles in the air, on most likely on fire. He's falling, falling far away from the city. Maybe the winds blowing out the fire or fueling it, I dunno I'm not clear about the science. But here's a scenario:
Pell falls in a lake, from an oasis--lucky huh? Remeber just how lucky OP characters can get. Now, he'd be drowning right? Well, I imagine that the doctor from that one scene was at the oasis at the right time. After all, someone living in a desert should have a good source of water--I know Alabasta had a drought but some people must have had barely enough water to get by--right?
So from here, Pell is saved from the water and nursed back to health by that doctor.
And lastly, I have this other crazy theory. Devil fruit users have a devil inside them right? Well I wonder, how does this effect them--aside from that power? I had this crazy idea--maybe the devil inside devil fruit users don't want to die?
Looks up the voltage required to kill someone