This story comes from Robert Velarde:
In 1960, Lewis and Joy took a trip to Greece. The trip was, at times, a struggle for Joy. During one outing in Mycenae to the Lion Gate, Joy, exhausted from the walk up a hill told Lewis that she needed a rest. They stopped off to the side. Then a tourist “came puffing up the hill,” as Gresham tells it, making “a snide comment” about Lewis and Joy not making it all the way up: “Well! You didn’t get very far, did you?”
And Lewis lost his cool. He walked over to the woman and punched her in the stomach. Just kidding. I just wanted to see if you were paying attention. But he did lose his cool and remarked to the woman, “Oh, go and have a heart attack!”
Not long after the woman was carried down the hill on a stretcher. Apparently, she did have a heart attack.