When Jennifer and Robert begin to trace the hidden message, Robert begins tracing above and to the right of Jennifer. When the completed message is shown, Robert's original part of the trace is no longer visible.
The psychiatrist's surname is spelled "Leiberman" on his office door. However, it is spelled "Lieberman" on Jennifer's bottle of pills.
Robert says that the Earth "revolves" on its own axis. However, the Earth in fact rotates on its axis.