Seems like most of the posters here haven't spent a lot of time playing the GTA games - this kind of thing is a staple of them since at least GTA3:
His thread title is alluding to the self-satisfied smugness of the person setting it all off (in the video signified by the flexing of interlocked fingers).
I've played all of them, a fire started accidentally in a car park has absolutely nothing to do with GTA or gaming in general.