Classicly

Meanwhile, the elevator operator, upon finding he could not move the elevator, returned to reassure the occupants. He went to the seventh floor and called down very cheerily, "Everything's all right, folks. If this'd happened before six o'clock there'd be plenty of blessed people around, but it's almost seven and the engineer ain't back from supper yet. It won't be but a little while though, and then—"

The operator became aware that only silence answered him. Had they been scared dumb? "You—hey you—down there—"

More silence. The operator frowned and crawled down into the shaft. He looked through the trap. Empty. "Well I'll be damned!" he said. And because an obvious situation was covered by an obvious answer, added, "All four of them crawled out and went home. Funny they couldn't stick around a few minutes."