Dave Lombardo might have gotten the boot from Slayer, but he's far from done with music. Lombardo has got his own band Philm currently and apparently is getting offers from orchestras to perform movie themes.
So what you're seeing here is Dave Lombardo performing with the Golden State Pops Orchestra, more specifically them doing a solid rendition of a bunch of movie themes. Lombardo comes in for the Ghost Rider theme which starts around 1:40. I've always been of the persuasion that orchestras can be ridiculously heavy and this only furthers my assumption.
Right as Lombardo comes in there's a slew of menacing low notes and the pounding of toms… damn dude, maybe Lombardo should join an orchestra full-time! This is seriously heavy!