In Brave New World we don't really start this Booker plot until more than halfway into the novel; things get tricky when there's a protagonist shift like you have here. (This is also one of the reasons Brave New World is criticized as being a far-from-perfect novel.) But once you get to Chapter Nine-ish, it's a shoo-in for a "Voyage and Return" discussion. John literally goes from one world to another, and in case you missed it, he explicitly says as much. Also, there's the title.
The dream stage doesn't last too long. In fact, it really only lasts the duration of the flight or so.
John's disillusionment sets in as soon as he sees the dehumanization in the World State. Clearly, this is not the place for him. The "shadow of oppression" which Booker discusses is particularly clear in the case of Linda, who is essentially enslaved by her dependence on soma.
Lenina revealing herself as a complete "strumpet" really pushes John to the edge. But it's Linda's death, and more importantly, the callous reaction of others to her death, that pushes him over it. John's soma-destroying freak-out is the summation of his Nightmare Stage.
John tries to make an escape by secluding himself at the lighthouse, but his self-mutilation there distorts what ought to be a return to normalcy, to his own world. His death may be thrilling, but it isn't exactly an escape and return. Or is it? If John defined the difference between the two worlds as being that of suffering and the absence of suffering, then his death was either the ultimate form of self-punishment, or the ultimate escape from suffering. What do you think?