Here`s my notes on Dran Draggore:

Map entry 54) Dran Draggore is here, in front of a mysterious altar. When you step at map entry 50, he will attack you! Be sure to continously keep moving to prevent Dran from hitting you with any of his powerful magic, Hit him once with the partys` best sword as he presents his flank and move away. It is no use to close a door between the party and Dran - he opens it again. The only thing that can stop him is a Wall of Force. Do not get trapped in alcoves like 43, northwest of 42, 48 and 54. After a few good hits you beat Dran to the floor, but he will raise to continue to attack. Now it is extremely important that he does not hit you! Why? That`s YOUR surprise, but stick to the same tactics! And one more thing - he still comes after you through the doors. Try!...

There are some similarities to you post above.

First memory this paragraph brought back was how I always used to hide behind doors in fights I were loosing. Meeting the mages on the level below Dran brought quite a shock when they actually reopened those doors and came after you. My compliments to the game designers.