Water heater dryfire - did I get lucky?

Drained my water heater (Suburban dual mode propane/electric) and didn’t realize the electric switch was on...noticed steam coming out the drain hole then a small ball of fire “poofed” out the drain. Gas was turned off at the propane tank and water heater switch at the panel inside the trailer (controls propane mode in my experience) was off. Quickly realized what was going on and turned off the electric switch on the heater.

Seems to be heating okay on electric only...did I get lucky and not burn out my element? Any explanation for the poof of flame? Hydrogen sulfide fireball from the dry element and gas in the heater tank?