Mystery Blue

As I was cycling to get the groceries, I came across this elaborate piece of street art.

I started blipping it and only seconds later noticed that the stone wall motif was three-dimensional!
Either someone has been working at this totally undisturbed, or they have an agreement with the city to decorate a few litter bins (these boxes are normally unicoloured grey).

But what's the message?

Right under the hole where you drop the litter is a guy filming with a video camera, and behind him is a bigger person who appears to push the video man into a stony pit.

Is it a warning of something? Harmless fun image? Or a prop for some student movie project?

Hard to tell...