The Real Hustle

I'm sure they didn't invent it, but The Real Hustle (BBC3...) did the same thing on a safe a year or two back.

They posed as shopping mall security guards and got the shopkeeper to open their safe to "check" it hadn't been emptied.

Then as soon as he'd entered the PIN, called him away on some "urgent" matter.

The other chap then took an IR image of the keypad, before entering the glowing digits into the safe, brightest last.