My aunt in Phoenix always kept instant mashed potato flakes for fixing thin gravy. She learned that from working at a truck stop cafe back in the 90s, and it was her go-to trick. Oatmeal is a smart move because it's basically just fiber that absorbs water. I remember one time I used leftover cooked rice to thicken a soup, and it worked but made it too starchy. Your idea with oatmeal probably blends in better with pasta sauce. It's cool how kitchen fails can lead to new tricks like this.

Seriously, was the dryer that dangerous to use for one night?

Always saw it as extra work, but this changes my view.