Say no
come up with an excuse to leave
tell them about the negative effects of drugs then say no
say you don't do drugs
tell them you can't
walk away
True, you do not want to start an exercise with tight joints and muscles.
The color of the sky is blue
You would want to talk to her in the back and use a moderate tone and show her the schedule showing that she was booked for a appointment another day and time. You then tell her that you are sorry for any inconvenience and that you will be expecting her on the right day of her appointment.
Symptoms may worsen, and the illness may progress. This could result in a less positive outcome for the patient; example: longer recovery process, terminal/chronic illness, or even longer term, death.