"I felt pretty good, like an amputated leg."
Marlowe says this after he's been hit over the head and is going unconscious. He says that he feels like he's jumping into a pool of black water. It also shows his sense of humor in the midst of a very bad situation.
"Say that again...the last thing you said."
Marlowe has just returned from being drugged for three days and calls on Ann. He hears her say, "Are you alright?." By hearing this Marlowe is able to piece together that she was out in the canyons when he was knocked out and Marriott was killed.
"That'll quiet your nerves, pally!"
Marlowe has just knocked the psych attendant over the head with a bed spring and knocked him out. He's been held here against his will and the orderly has kept coming in and knocking him out. Now the tables have turned and he's left the orderly unconscious locked in his room.