I need to replace the shower pan , trying to find a way around it
How many pointed sticks can you find?
Definitely sounds like a crack in the heat exchanger causing the wrong type of ignition/burn. I have seen it a million times - it will only get worse the longer you wait!
Do CPR on the people that fell over in the Pentecostal spirit, say Sha-na-na-na-na-na-na-na-na and pretend you're casting a spell on that person then throw a bucket of water on the head of the victim because of the fact that you'll insist that you saw that the victim was on fire. Then, if you can, throw a fire blanket on the victim. Then pretend to tell the victim about his or her future and ask for money insinuating that the more they give, the better his or her future will be, they eat that stuff up.