If there is no visible gill movement, chances are it's no longer with us. That being said, there is a study out showing that shark embryos will stop moving and breathing if they sense a predator near the egg.
There is a viable solution, though. Get a small breeder net or a plastic "Critter Keeper". Then use a razor to slowly trim the edge of the egg (avoid the body, yolk and umbilical). Poor the egg into the net or keeper and see if your shark is alive or not. If it is, keep it isolated in the tank until the yolk is fully absorbed. If not, you can get it out of the system so the ammonia from the dead body won't disrupt your chemistry.