As long as all of your staff is well trained in CPI you should be fine. I work in a free standing psych inpt unit with mostly female staff, a couple of our nurses are males and maybe half of our MHT's are males. When we have a pt who we know is escalating we use prevention methods, try to talk the pt down, offer the quiet room, PRN's. If someone flips we use our restraint training. We have called the police on a couple of occasions, once on a weekend when there were only two nurses and three MHT's (we don't have security) we had a pt attack an MHT on admit in an attempt to escape. He was large and another MHT called for help. We saw on video what was happening and due to our low staffing and his size and aggression we called 911 then went to assist. We were able to get him on the ground safely by the time the police arrived. I think it's all in your training. Make sure you know how to subdue someone who is stronger than you, there are ways you can move their arms that make it harder for them to fight. Make sure you can pull up IM's quickly, and most importantly, make sure you work with people whom you trust. One thing you guys might want to do is request more crisis, escalation, and restraint training.