Below I will explain in details what actions I took at the time of the incident.
First step: I politely removed myself from the area the person was in, just in case "they" decide to harm myself and themselves.
Second step: I call the police department and they were familiar with the individual and their mental conditions. The police department called the ambulance, so that they could transport the individual to the Psychiatric Hospital.
Third step: I opened up the door half way and asked the individual were they hungry to take their mind off the subject, without going all the way in. I knew this individual had a violent past, so I was not taking any chances.