it's as if everything is coming to a head, and for all the years he has tried to quieten the voices in his head, now they are at the forefront of his mind. Something is happening that he can no longer ignore. he can no longer shut away his own feelings and thoughts
Yes, something volcanic is happening in Maurice's psyche, and whatever one personally thinks of hypnosis the session with Lasker Jones does seem to have the effect of even further loosening and freeing Maurice's mind (in the next few chapters especially.) So I think it might have happened at just the right time.