The fire started in the kitchen when john was making dinner, A Paper got blown over on the stove and caught on fire from thermal energy. The fire got out of control to fast for him to stop it, he called 911 and tried getting out. on his way getting out there was a log of wood that feel out of the wall, the only option he had was to move it with his hand.
how john uses his super powers
WOW that was cool!
John has had the same gas grill his whole life He felt the burning piece of wood burning his flesh off his hand then he had a flashback. When he was 10 years old be burnt his hand on a hot stove. A day after that incident his mom got hit by a truck when she was on a bike. so the reaction of having greater mass to an other object that has smaller mass really made an impact.
When John arrived at the hospital the doctors were speaking privately and he heard them talking saying that he can keep the pain or he has to get a new hand. John realized that out of his right hand comes fire and out of his left hand there is propane to come together and make a chemical reaction.
So this is how he found out how to use his super powers, even thinking of the house fire he had he shoots fire out of his hand.