The Apple A Day Affair - S3-E27
Revealing mistake: Gardner and Illya are chained to a mine shaft post and the Thrush bad guys trigger a cave-in to seal them in. As the debris falls, you can see the entire "stone" wall behind them rock and wobble flimsily from side to side. (00:23:50)
Answer: He must have ridden in an Eaton's store elevator while he was in Canada at some point. For some reason, this elevator reminds him of it. The show's original concept had Solo being a Canadian, so this may be a minor nod to that fact.
raywest ★