Ive got the converters to plug my ps4 into your fridge, but howd he change the input on the screen?
I’m sure there was a little ‘input’ button within reach.

He had access to the back of the monitor. It was just mounted on a frame. He probably unplugged the input and plugged into the same port.

https://www.wxii12.com/article/passenger-takes-over-airport-monitor-plays-video-game-while-waiting-for-flight/30573509