That’s right kids, it’s head canon TPoH music time!
I’m not sure why so much of the Poirot soundtrack feels so TPoH-ish to me, but this one and ‘redemption’ from the 2010 Orient Express in particular feel very resonant of it. Maybe it’s the slightly eerie sense of foreboding, or the sophisticated charm with a sense of underlying threat, but it does seem to fit in my mind’s soundtrack of it.