Yox only whines about how he should not have done it.

I tried quitting game, reloading, waiting for some time and returning but nothing.

I finally just killed him, but that did not finish the quest either ;( .

Not sure if messes any thing up or not, but got tired of trying to get the dialogue to come up.

I have moved on now, but wanted to mention that that quest seems to have some problems.

[ I did not try a reload from before I entered the laboratory, Just to tired of redoing so many quest battle's to get it all right. ]

Several people have reported this problem, at least in a couple cases with his former master showing up dead in the cave after being healed.