The idea sounds interesting, however there is one deciding factor whether this would work or not:
- How fast is Chimaeron walking in Phase2?
You are right, kiting him out of his room is a reasonable idea - in case your DPS can keep up with the boss. You have to keep in mind, that even if Chimaeron walks "only" with 130% walkspeed, you could theoretically use aspect of the pack from a Hunter to keep up with him. But for one, caster won't do too much damage anymore and two, NPCs tend to walk the shortest possible line around corners, which a human can't do.
--> Your idea works in case you can keep up with the boss. And if that's the case, you can theoretically kite him for hours, since your tank would be fast enough to constantly run in circles aswell.
But even if you can't keep up with Chimaeron, the area near the Elevator looks perfectly fine to abuse mob-pathing. A clever warlock could certainly kill him from 20% to zero there.