Crank it Up: There are 4 large inserts at the bottom of the playfield.
Switch, Snake, Coffin, Cross
Hitting those objects on the playfield enough times, or collecting them via lit inserts on the major shots (notice the snake, switch and cross on the major shots) lights Crank it Up at the scoop. This will be a blue light. Hit the scoop and then select the song you want to play during Crank it Up-which has its own set of rules for each song. Or or you can immediately take the 5MIL, but CIU is worth more usually-assuming you don't drain quickly.
CIU can be repeated in the game until ultimately you reach End of the Line, but right now we are just trying to break the 25MIL barrier right?