The best thing to do is to read the Act itself as well as refer to the PA Crime Code. And by the way, this is covered in the 40 hour Act 235 Certification course. With that said, if you are NOT a sworn law enforcement officer, it is NOT your job to pursue, apprehend and arrest suspects. As a security officer, it is your job to protect people and/or property. In the conduct of your duty, your obligation is to avoid having to use force as much as possible. Just as is the case with LEO’s, you will have to document incidents ad you will be held accountable for your actions. So, the short answer is you can use restraint if you have to do so to prevent someone from getting hurt. And the best course of action is to call 911 and stand by for the Police to deal with and apprehend a violent criminal actor. If you restrain someone (which is the use of physical force), it cannot be for any other reason than to protect life. And if you can restrain them until the Police arrive, great. But if you cannot, you should not pursue!