As Mark Sloan is walking down the hallway, Nurse Delores reaches through a doorway, grabs him by his right sleeve, and yanks him into the room. As the shot continues, after a cut, she now is pulling him by his left sleeve.
When starting a confession, the penitent normally says, "Bless me, Father, for I have sinned;" not "Forgive me, Father," as the man does in the opening scene. However, as the supposed penitent is a blackmailer and is accusing the priest, he can be excused for using different wording.
Given that the first two seasons were filmed in Colorado, but the series is set in the Los Angeles area, the cars should have California plates, but in multiple episodes, Colorado plates can be seen on the cars.