Lynne is sitting on a sofa with an unnamed friend. The friend tells Lynne that her doctor has told her to give up most of her vices. Lynne asks what they are to which the friend replies that they are alcohol, coffee, chocolate and the like. Lynne shows some sympathy before asking her what the vice is that she can't give up. The friend tells Lynne it is her doctor and she leaves with him.
At first glance it looks as though Lynne and her friend are at someone's house. However by the end we realise that they are at the doctor's, but waiting for different reasons. The friend, who may now not be a friend but merely a woman in the waiting room, is waiting for her doctor boyfriend but Lynne is probably just waiting for her appointment. Her ailment may be the same as the one we were wondering about before.
The woman, we will no longer refer to her as a friend, mentions her vices are alcohol, coffee, chocolate and the like. 'The like' could refer to any number of vices but of the ones that a doctor would recommend you to stop she must be referring to smoking and recreational drug use. You can understand that she would not want to tell a complete stranger how many valium she takes in a given week but smoking is not yet the taboo it has become.
One of her vices, her doctor, is something she has been officially told not to give up. If this is a normal relationship, then there is no reason to call it vice. That is of course unless the doctor is carrying a disease or insists on some dangerous bedroom games. Maybe the doctor is the one with the uncontrollable heroin habit and is very careless with where he gets his needles from, which is ironic considering how professional he is inside his surgery. His professionalism does not extend to the waiting room, where he is now not only breaching the medical code by engaging in a relationship with a patient, but also neglecting his other patient by walking out before surgery time has finished for the day. So Lynne's appointment isn't important enough? Lynne must not know that this is her doctor as she would be furious. Now she has to make another appointment for no reason other than this doctor needed his fix of intravenous drugs and a bit of howsyerfather.