This type of thing happens. A friend of mine who is LEO went to his girlfriend and broke up with her saying he made a mistake and was going back to his family. He went back to his matrimonial home. A short time later the police showed up and apprehended him under the mental health act. She apparently called police saying she broke up with him and that he said "I can't live without you." She then said he left her apartment and was going to get his work gun to kill himself. Well that never happened but that is what she told police. The cops went to his house and apprehended him under the mental health act. I went to the hospital that night and after the doctors assessment he was immediately released. He had to do a wellness check with his service before being allowed back on the road and armed.
It was her word. The cops took it. You would never get a charge or conviction for mischief unless she gave a statement. Same thing goes for this example provided. Her ex would have to give a statement saying I lied.
I'm not agreeing with the conduct but on occasion the police have no discretion and "shall" do some things. Its unfortunate that she had to go through that and it probably could have been better handled by the cops but I'm confused if it was MHA why was a crown involved? Mayne for the firearm seizure. Maybe 117 public safety?