Actually, possible.
A safety incurred during a PAT (or two-point conversion attempt) counts as a single point. So if Ohio State fumbled on a two-point conversion attempt, Michigan State recovered and retreated back into the end zone where they were tackled--that would give Ohio State a one-point safety...which could end a game in 4th overtime as a one-point win.
The NCAA rule is as follows:
"On a try attempt… a Team A fumble that is recovered in the Team B end zone by Team B. RULING: Safety, award Team A one point (Rules 8-3-1 and 8-5-1)."
Here's an example of the one-point safety actually occurring...