If I Love Lucy hadn't been an excuse for Mestral to go out with Maggie (https://memory-alpha.fandom.com/wiki/I_Love_Lucy), which episode could he have seen that night? If a new episode: Where in the 1957-1958 timeline was he at that moment? Season 6 episode "Lucy Gets Chummy With the Neighbors" aired January 10, 1957, while the series finale "The Ricardos Dedicate a Statue" aired April 4, 1957. Subsequent hour-long episodes were aired under the title The Lucille Ball-Desi Arnaz Show (later The Lucy-Desi Comedy Hour). If syndication: I don't know if this is possible, but part of me hopes it was "Lucy Is Envious" (the Women From Mars episode).