Replace the floor ? hell yes its gone. I mean gone to the point that I can see the joists under it. The joists are being replaced, they look like a burnt match.
Not the first time I've used space heaters. Put one on each circuit breaker[bedroom breaker, living room breaker,etc] and they will run forever. Put 2 on a breaker and it trips immediately. No fire, the breaker does it's job and shuts the circuit down.
Lucky? I have 2 smoke detectors per unit as required by code. I don't need to "get" any.