Some of the drivel from ****** lawyer types is perplexing.
Whilst passengers are on board, who accepts the responsibility for their safety if a fire is detected on or near the aircraft. The crew does that's who, not ground staff or the airport manager or some other tosser. Once a passenger walks on or is helped on board the crew are responsible. If a pilot is on board then via the chain of command they are responsible but unlikely to usurp the normal procedural conduct if something risking the passengers safety is detected. Whether the aircraft is pushed back and taxiing is a moot point. The only people qualified to order an evacuation, fight fire, or God knows what else are the crew. The crew can be Flight Attendants and or Pilots. If you're at the gate, boarding and an APU fire warning for example occurs or some other threat to safety, whom is responsible? The crew that's who.