Prevention covers everything that stops a fire starting: controlling ignition sources, managing waste and storage, keeping electrical installations maintained and taking arson risk seriously. Protection is the built-in measures that limit a fire once it starts, from detection and alarms to fire doors, compartmentation and protected means of escape. These two P's split fire safety into before ignition and after ignition, which is a genuinely useful way to structure a walk around any building.
Preparedness, or Planning, is the human layer: an evacuation strategy people know, staff trained for their role, drills where appropriate and clear information for residents. People, or Property, is the reminder of what the effort is for. Versions ending in People tend to prompt better questions, because they push the trainer to discuss occupants who need extra help escaping, which is where a person-centred fire risk assessment enters the picture in housing.