Thanks for your comment!
The difficulty progression is something that changed around a lot during the development process. As it is, the time between swaps decreases by 25% every minute, according to an exponential function:
For game jam games, I think it's a good idea to make the average play length short, around five minutes or less. This is why swaps happen more and more frequently, to make things harder. Fires speed up, too!
I definitely like your idea of a "learning mode". Ideally, I wanted to make an interactive tutorial that allowed players to drive around in a sort of sandbox level, so each player could practice each role without any time pressure. I didn't end up having time for this during the jam, unfortunately. If I ever come back to working on this game, that'll be one of my goals.