I had one like that,when he caught that smell nothing would stop him.
A concrete slab with chain link fence with a chain link cover might would slow him down some.
I bet your heater is burnt up and shorting,pull one of the wires off the heater,usually flat cooper strip with a nut holding it tight,turn everything on and see if the shorts is gone,if still shorting pull the other strip off.
This is a common problem with hot tubs.
If all clear it is your...