When Dr. Burton and the detective are talking at the Robertson residence after being informed of Albert's escape from the mental institution, the phone rings once and Albert's mother goes to retrieve it. The detective stops her and spends twelve seconds convincing her to keep him on the phone- it never rings again but she manages to pick up the receiver and Albert speaks to her on the other end.
When Albert escapes from the hospital and is in the shopping center parking lot looking for a car to steal, the side door of the van the cameraman is riding in is visible during a tracking shot as Albert tips his hat to a lady.
On the audio, the girl in the pool hall is heard choking before Albert gets his hands around her neck.