I particularly enjoyed Delly's review of this film and agree that Howard is not the only "damaged" character. Howard is rather ruthlessly "set-up" by the script, but there is no evidence that his previous employer is actually dead or, if she is, that he murdered her. Howard doesn't know and neither do we. In terror and confusion at seeing the woman lying there, he bolts. However, he never actually harms Helen Gordon, no matter how enraged he is. Indeed, he reacts with horror at Helen's fainting spell and the fact that he is holding a pair of scissors...then he resumes his tidying up and greets the recovered Helen with the almost pathetic " I'm very tired now. I think I'll go home". Frankly, I don't think he's a psychopath. A sick puppy, certainly, but not a psychopath.
The problem with Howard is that he has no real male identity. He wanted to serve his country, but his mental condition denies him a place in the army. He is singularly rootless and isolated: no wife, no girl, no home (again, at least as far as we know). And, he does a woman's job - "Floor's are my speciality". Helen's niece ruthlessly strips away this pride in his thoroughness by exclaiming caustically that she would want a man with a real job. Also, although he finds himself strongly attracted to Helen, he is unable or unwilling to do more than scare her by making a strong sexual pass. He is remarkably powerless - can't fight, can't work, can't make love.
Helen is justifiably terrified, however. She tries to connect to him but, finding that he doesn't respond normally (i.e. way outside the comfort zone provided by her rose-tinted memories of husband Ned), unwittingly presses all Howard's buttons by lying to him in her attempt to escape.
Both characters, trapped in the house, trapped by fear, neuroses, rage and memory, deserve sympathy. I know the sudden ending has disappointed some reviewers, but I felt it fitted well, as it offered a kind of release to the characters. Helen is freed, I think, from the past. When Howard tries on her husband's army coat, Helen's disgusted reaction is highlighted. She no doubt feels that the "sacredness" of Ned's possessions has been violated but, hopefully, her need to keep everything "untouched" has been lost in the reality of her own struggle with danger. Perhaps she can move on.
Howard is also freed - from his endless cycle of anger, hurt and violence. Whether he moves on to treatment or to jail is debatable, but I hope it's the former.
Great performances from Ryan and Lupino. I prefer "On Dangerous Ground", but this is pretty good too.