You know, thinking about it, I don't think Holmes did come to the tenant's rescue. He told Gregson her husband was Gorgiano's killer, and also signalled to her to trick her into coming over. If Holmes hadn't got involved, Lucca would still have killed Gorgiano but then he and his wife could have slipped away without the police necessarily knowing he'd been involved. (Though Lucca would probably have turned himself in - he'd given information to the New York police, so they knew about his connection with Gorgiano.)

*sighs* Think it's a case of great minds realising there's only one decent rhyme for "Warren" ^^" And as I've said elsewhere, you've come up with the better clerihew... (^^)