Leaking tension

Mr Wong, the famous detective, and his professorial friend are investigating a murder in a rich man's San Francisco mansion. A ladder to a french door on the second floor has been found. Leaning over the balcony to look at it, Mr Wong says, " I don't understand that at all."

"What? That our Mr X should have to force an entrance into the house?" asks the professor.

"Or Mrs X," Wong replies with significant emphasis on the Mrs. "Or Miss X."

It plays out funnily. All the tension dissolves with that "(pause) or Miss". Even Karloff can't keep it dramatic.