It’s not a scientific answer, it depends on the shark the circumstances as how it came to be outside of the water. How much energy it expended, but according to my friend experience shark can stay alive outside of the water only 3-5 minutes if there’s dry condition. But when we treat correctly like keep shark in wet condition, maintain the humidity they can stay alive for 10-15 minutes depends to species and size. But we have standard time for shark handling, especially in by catch case, no more 3 minutes to handling shark outside water.