The fire boss throws fire balls at you.  You have to dodge them while
dodging the small fire ghosts.  There are four sprinklers.  You can get
two of them by just walking and turning.  But the other two are blocked
by bushes.  Get the fire boss to throw fire balls at the bushes to burn
them down.  Once he does, turn the sprinklers on and use the Tome of
Doom.
The combination of the lock in the bank in Weird Wild West is 1-3-7.