Book one: Marcus runs away from Ethan when stuff is getting real during a mania phase. Stealing Betsy to do so. Ethan finds him. Afterwards Marcus goes to the isle of white until he he returns to a "norm" phase.
"If we had keen vision and feeling for all ordinary human life it would be like hearing the grass grow and the squirrel's heart beat, and we should die of the roar which lies on the other side of silence."