Ah, seems so.

For the sake of potential dialogue, I'll say 1!

I'm gonna say 1. it might be a good way to stall him. keep him in there until he's mentally weakened, then once he has to get out attack (I do hope I interpreted the description of the circle right)

1. Then kill it dead!

I say try to talk to him. If his powers are so heightened and he was hurt by his master in such a way it makes sense that he would want to discuss matters. He is also mentally unstable so when we talk we will have to be cautious. But I get the feeling that he isn't really controling the ID and that it is using him to get more hosts before taking control of his body. We can ask what he has planned and inform him his master left town, fleeing away from his power. That would give him a major ego boost and maybe allow us to win his trust long enough to disrupt the circle, or make it so Arty can cast a powerful spell within quickly to destroy all the Ids and then get back out of the cave before the spell's power makes it collapse.

I'm going to go with one two, he might not be able to be reasoned with but you can ask what the heck he's talking about when he says 'master.

Attacking already failed, we'll never make it to the exit in time, and I don't trust this guy's sanity enough to assume he's bluffing. I'll come out and talk. Negotiating may not improve matters, but given that we're currently at "sudden fiery death," it would be hard to make the situation worse. Even stalling for time would be an improvement.

Oh... I just realized. I think we may have found the person we were looking for. Now I wish we hadn't.