Police came round (I phoned them, they had to record the incident even though I wasn't pressing charges—joys of bureaucracy according to the officer in question). No charges, no need for medical attention or anything like that.

Bit later, someone went to see blokie next door (probably registered carer or something like that). Current theory is that he may be agoraphobic—he certainly doesn't like letting people in, I know that much.

No further repercussions as of me leaving for work, save that I'm even more paranoid than normal.