Darcy had been so worried about Ashley that he hadn't had much space in his brain for worrying about anything else. For example, the fact that they were clearly living together and sleeping together despite only being engaged, or the fact that he was currently sporting modern pajamas as opposed to actual clothing.
When he heard the knock, he did pull on a dressing gown before he opened the door.
"Dr Morgan. Thank you so much for coming." He stepped aside to let him in.