In Now You See Me, when Morgan Freeman explains to the detective on how the Four Horseman robbed the bank, he mentions that they replaced the real money (while in the secured transport truck) with flash paper.
This does not explain how the paper in the bank got ignited, and no ignition/stimulator left in the scene as evidence.
Who/What/When ignited the flash paper in the bank on time?
- There had to be some timer/delay mechanism on the platform, or something similar - but in the frames we see - there is nothing.