its easy to say, but you shouldnt feel to bad, i know i would probably feel the same if i was in your shoes, but your friend(neighbour) seemed really understanding, you gave concern and apologised and followed through by going round to see she was ok, it seems no harm done as such, but it sounds to me he got spooked somehow, like some of the others have said, dont feel to bad, just keep an eye on him, and see how he reacts to other people and surroundings, goodluck