Going to apologise to someone you've just been
talking to very shortly after having bid them fairwell, for something you didn't realise you'd done wrong.
From the so-called "Bigotgate" affair (28th April 2010) during the 2010 UK General Elections, when PM Gordon Brown had to apologise to a lady in Rochdale he'd just spoken to, for calling her "bigoted" after he had spoken to her and got
in the car to leave, not realising his radio mic was still on.