What kind of "clear and present mortal danger to public safety" would involve an eviction before contacting the authorities and likely arrest (followed by abandonment and eviction in absentia)?

Landlord overhears tenant saying, “I’ve got a bunch of guns in my apartment and I’m going to start a massacre”.

Landlord is entirely justified in immediately changing the locks and contacting law enforcement after.

Mere hearsay is not sufficient cause for eviction. Might be grounds for calling the cops, but not locking someone out of their home. For all the landlord knows it was a TV show.

Could you please find an example of a tenant being legally kicked out by the landlord himself without even involving the law enforcement or a court of law ?