An epiphany, a shocking revelation that occurs when doing the most mundane of tasks, such as showering. This could be the solution to a long-unresolved problem.
Mike's been wondering what to do with the corpses for a while, as they're very incriminating evidence, and are also starting to smell real bad... but then yesterday he had a showertime epiphany: dump them in the river!
When you're going so fast (i.e. on a skateboard, rollerblades etc.) you don't know where you're headed, and you can't stop.