Personal Safety and Use of Force
Before contact
Assess the situation before you close distance: numbers, weapons, exits, lighting, backup, and your own physical readiness. Maintain situational awareness by establishing a baseline and watching for anomalies, and recognize pre-attack indicators (clenched fists, blading of the body, scanning exits, sudden quiet, target glance). Keep a reactionary gap - roughly six to eight metres - so you have time to react, stand bladed with hands free, and never let yourself be cornered. Know the difference between cover (stops projectiles) and concealment (hides you). Use check-in procedures when working alone and call for police or backup early.
The legal framework for force
Criminal Code s.25 (authorized by law), s.26 (excessive force is criminal), s.27 (preventing an offence), s.34 (self-defence: reasonable belief of force or threat, a defensive purpose, and a response that is reasonable in the circumstances), s.35 (defence of property). Every use of force must satisfy five tests: lawful authority, reasonable grounds, necessity, proportionality, and the force stops the moment the threat ends. Options are graduated - presence, verbal direction, escort/control techniques, handcuffs only if trained, authorized and necessary.
After force
Render first aid, request medical help, secure the scene, notify police and your supervisor, preserve video and physical evidence, complete a use-of-force report, and expect review.
Trap: assuming self-defence requires retreat (it does not, though retreat is a factor); assuming an assault requires injury (the apprehension of imminent force is enough); and cuffing or searching everyone detained 'for safety'.
Rule of thumb: if you cannot justify it as necessary, proportional and stopped when the resistance stopped, do not do it.