Evil-Cooper comes back to the hotel room and finds Darya on the phone with someone and then he walks over to Chantal after killing Darya in episode 1x02 "Part 2".
The Scooby gang take refuge from the Knights of Byzantium. From episode 5x20 "Spiral".
From episode 1x15 "As Good as It Getz".
From episode 1x04 "Fever".