Not sure if you saw the bonus panel, but the author was also confused by this one, 8 years later. I think the joke is that this is a flashback, showing the man on a date (that he’s narrating to a police officer that’s interviewing him, in the caption). He remembers his date as being into his delusions, because he’s a paranoid schizophrenic, but the likely reality is that it didn’t happen that way.