In both films, the scene where two characters (Bob and Clive in 1934, Ben and Jo in 1956) attend a service at a church that seems to be involved with the plot, and during a hymn, sing their observations to one another to avoid suspicion. Especially with Doris Day's powerful voice being quite startling to the people in front of them.
To elaborate, Ben and Jo had gotten a lead on Hank's location. So they'd left their friends (who hadn't even known about Hank's kidnapping) in their hotel suite. By the time the McKennas have returned to the hotel. All their friends had fallen asleep while waiting up for them.
"You English intellectuals will be the death of us all!"