Same thing happened to me, and after it occuring twice, I said "Why am I bothering with this?" and threw a Planetar into the room... That pretty much solved my problem... But umm if you are soloing without ToB, I would suggest... Bah, I can't think of anything... Laying more cloudkills should nuke him before he gets to it, as he was at Badly Injured before he did it to me.
