Elwin had "loopin' supers" running, which is why he can, um, loop the supers. This can be awarded from the pops/newton balls on the left/tobin's spirit guide (mystery). It was only worth about 240 mil, so that's far from the bulk of his score. I would be very surprised if a game mode that has inserts screened was taken out at this point. Many games have had 'loop the following shot until you f*ck it up' modes. I wouldn't be surprised if the timing was tightened up, though: the grace period seemed quite long. The Dead Flip stream got a maximum of 2-3 supers during the mode, Elwin's a bit better than Danger...
From watching the game footage released so far, the Super Jackpot acts a bit like the Song Jackpot on AC/DC, except it resets at end of ball instead of every time you collect it. It has *nothing* to do with multiball, (except that one of several ways to light it in S.F. Multiball). Not all Jackpots are a multiball feature, folks.