How to create a randomized algorithm function

I am creating a reaction game using a series of lasers and LRDs and need to make a function which waits for a specific pin in portb to be triggered high before it can move onto waiting for the next pin to be triggered. The time lasped before the "game loses" needs to get exponentially faster as the game goes on.

I am using statements such as if(input(PIN_B0)==1 generate_tone(G_note[2], 1000); but unsure how to write in c "wait x amount of time, if trigger move onto next random pin or no trigger go to lose function.

Any help would be greatly appreciated Angela