The train arrives and Guy forgets the whole silly conversation when his wife, sensing a cash cow, backs out on the promised divorce. They get in a heated argument in front of her co-workers. Later on she's at a carnival when Bruno shows up and strangles her to death. Bruno then contacts a horrified Guy and tells him that now it's Guy's turn kill his father.
If I had to rank Hitchcock movies I would place SOAT somewhere in the Top 20. It's an entertaining viewing with some interesting shots and a nice amount of dark humor. On the other hand it's not re-watchable (like PSYCHO or VERTIGO) and the character of Guy is a total idiot. All of his problems would have disappeared if he had just manned up from the beginning, but instead he spent the majority of the movie whimpering like spineless pussy. Worth a rent and that's it.