I don't get the hand-wringing about Purdue firing their OC, as if someone is going to come in and install a new offense in two weeks that will right the ship. At best we'll see a new wrinkle somewhere, and perhaps a different tempo/approach to play-calling and opening drive. I'm guessing that Walters wanted to put up the now-hiring flag sooner rather than later, and that someone on the staff will assume interim play-calling. Whomever is interim play caller is going to be auditioning himself, so I'd still expect competence.
If I was a Purdue fan looking at the rest of the season, I'd probably also be looking to basketball season and coordinator search discussions.