I was sure the doctor held the key to Karls guilt. On the actual night, when Karl returned to the strip, the doctor appeared to be sniffing something - smoke?- when he stood next to Karl.
I often think there are soap spies involved as it often happens very similar story lines in several soaps and perhaps culminating at roughly the same time.
In real life Debbie Dingle (Emmerdale) is the sister of Jamie Lomas (EastEnders) who is married to Kim Marsh (Coronation Street) so perhaps they talk to each other.