From episode #111, The Case of the Waylaid Wolf
When Orvel Kingman and Al enter Perry's apartment, watch the action with the door.
Orvel says "Shut the door Al." Al proceeds to do so, but we never see the door
actually closed. Al is in front of Perry.
A bit later, as Orvel walks in and Al is closing the door, Perry says, with his lips
barely moving, "I'll close the door." The camera angle changes, and Perry closes
the once again open door. Al is suddenly behind Perry.
[Trivia][Perry Mason TV Series]