Being Prepared Guarantees Nothing
On the demi-plane between the planes of fire and water, we sense we are nearing the final encounter. We have checked one place where the villain might be and he wasn't there. There is just one more place to check.
'Let's use these scrolls of resist energy before going through these double doors', says Boycey. 'There seems little point in wasting them, and now is probably the best time.'
We agree, and use the scrolls to cast resist energy on each of us, choosing fire as the energy to be resisted. It's not a difficult choice when on this demi-plane, particularly as water isn't an energy type. 'Okay, let's make an entrance.'
'You open the doors, and...'
'We explode! Ha ha!'
'...you kinda do.'
'I was joking! It was a joke!'
'Not a funny one, Aramil.'
A burst of fire envelopes us as the doors open. 'What a great leader we have! Good job on suggesting the scrolls, Boycey', says Boycey, and in his moment of hubris forgets to dodge, failing his reflex saving throw and getting fully engulfed by the fireball.
Before us stands the villain, holding a necklace of fireballs missing its most expensive bead. An extended surprise round continues with him monologuing, an NPC class feature, apparently. His little, self-promotional speech ends with, 'I will let you choose whether to burn or drown!'
'Burn, please!'