Yup, that would be a scary type of experience for you.
Reptiles can hold their breaths for ages. Being cold blooded, they don't need as much oxygen as warmblooded animals who need the extra to burn calories for body heat. It's amazing how long they can go without a breath - ask anyone who's had a snake attached to a body part, and tried to encouraging it to let go by submerging it under water. It's also a reason why gas anesthesia is tricky to use on reptiles - sometimes they get one whiff of the gas and stop breathing after an insufficient dose of the drugs, then wake up later, partway through surgery.
I tend to wait at least 12 hours before pronouncing a reptile dead, or wait for rigor mortis to set in. After that, I'm sure they've moved on to the next plane.