Niska picks up a book from Dr. George Millican's shelf and speaks, without opening it, "And once you are awake, you shall remain awake eternally." That is by Friedrich Nietzsche (1977) from "The Portable Nietzsche", p.201, Penguin.
Dr. George Millican says to Niska, "How many angels can dance on the head of a pin?". It is a phrase that refers to wasting time debating topics of no practical value, or on questions whose answers hold no intellectual consequence, while more urgent concerns accumulate.
The book Niska has is "The Ghost in the Machine" by Arthur Koestler, the Hungarian-born author and journalist, known for his cult classic work "Darkness at Noon". It has hand written message "To, Niska, Primum non nocere, Love, D.E. (means, David Elster). Primum non nocere is a Latin phrase, also called Hippocratic injunction, Dictum Primum non nocere, that means "first, do no harm".