Either find a new mark or roll with it. If you keep going with someone in the know it's very important to walk away and not engage the person in conversation. Remember, people in the room would not be able to hear the thoughts of someone in a coma. Maybe you could go Inception on your mark. Pretend to have a casual conversation with a friend who is the marks path. Say something like, "It's been so long the brain is probably making up events to explain our attempts to wake the subject," or "Brain scans show activity indicating the subject is cognitive of our input, but the signals show a dream-like state." Then continue with a casual conversation about school, work, the weather, etc. or walk away.