Ketubot 30: When a Thief Is Caught Red-handed, Yet He May Not Have to Pay

The case of illicit relationships and the penalty that would need to be paid - which did not align with the view of R. Nechuniyah ben HaKaneh. He draws the connection to a shabbat violation that comes together with a monetary penalty, and how the perpetrator is only obligated on one punishment (and how Abaye and Rava understand his approach). Also, what happens if a zar decides to eat terumah (a karet violation), and stole it from a kohen - shouldn't he be exempt from paying for terumah because of the more extreme punishment. But what if you could get the terumah back? What if the terumah was liquid terumah??