Quote 25
"Free, free!" the Savage shouted, and with one hand continued to throw the soma into the area while, with the other, he punched the indistinguishable faces of his assailants. "Free!" And suddenly there was Helmholtz at his side —"Good old Helmholtz!"—also punching—"Men at last!"—and in the interval also throwing the poison out by handfuls through the open window. "Yes, men! men!" and there was no more poison left. He picked up the cash-box and showed them its black emptiness. "You're free!"
Howling, the Deltas charged with a redoubled fury. (15.41-2)
Check out the line, "Men at last!" What John is probably getting at here is the notion of infants as opposed to adults. Without soma, these Deltas can be adults—can be men—instead of bottled babies. This is exactly what Bernard was getting at with Lenina when he told her that they shouldn't have gone to bed "like infants."
Quote 26
"But why is it prohibited?" asked the Savage. In the excitement of meeting a man who had read Shakespeare he had momentarily forgotten everything else.
The Controller shrugged his shoulders. "Because it's old; that's the chief reason. […] Particularly when they're beautiful. Beauty's attractive, and we don't want people to be attracted by old things. We want them to like the new ones." (16.14-7)
Mustapha essentially imprisons the citizens of the World State by removing their ability to choose. If they can't see any alternative to the present (think of the hypnopaedic saying "was and will make me ill"—it's all about living in the moment), they can't wish for anything different. This is why the past is dangerous; it offers alternatives.
Quote 27
"But I don't want comfort. I want God, I want poetry, I want real danger, I want freedom, I want goodness. I want sin."
"In fact," said Mustapha Mond, "you're claiming the right to be unhappy."
"All right then," said the Savage defiantly, "I'm claiming the right to be unhappy."
"Not to mention the right to grow old and ugly and impotent; the right to have syphilis and cancer; the right to have too little to eat; the right to be lousy; the right to live in constant apprehension of what may happen to-morrow; the right to catch typhoid; the right to be tortured by unspeakable pains of every kind." There was a long silence.
"I claim them all," said the Savage at last. (17.62-6)
John finally puts the proper name on the freedom that he, Helmholtz, and (at one point) Bernard all claimed: the freedom to suffer.