I agree with you up until the last part he should have not went up stairs :2 cents:
You gotta do something but what you don't do is kick in someone's door and draw down on them with a weapon unless you're a cop....he's lucky to only be facing charges.
He should have called the cops, armed himself with reasonable protection just in case he had to try and save someone's life before the cops arrived and knock at the person's door to ask about the noise then protect himself if he's attacked.
The guy doesn't sound as chivalrous as he sounds imbalanced and paranoid...I gotta tell you though, someone kicks my door in waving a sword, yelling, "where is she.." that will probably be the last door he kicks in.