This is from the third season episode, "Losing The Light": In chapter 5, Alice and Tanya are talking outside of the hospital, and Alice says she is visiting a friend. As the camera switches to Tanya, who replies "I hope they're alright", two doctors can be seen approaching from several feet behind Tanya, and pass her and Alice. The camera switches to Alice for her reply, and then back to Tanya, where the same two doctors are once again approaching from several feet behind Tanya.

(These docs can't even find the entrance, I'd hate to see them in Emergency.)