Mary Mac: the shark will come out. I work at a fish store and we've had about 4 or 5 shark eggs, all of which hatched healthy sharks. One egg had to be opened a little bit, only do it if the baby is done with yolk sack, and it looks like it cant do it (over 12 hours after sac is gone), after that time the baby sharks metabolism is so fast it will start to devestate it's fat reserves. Dont use a scalpal or anything sharp and long. Take off the top and while keeping the egg still, lightly scrape the egg with a razor blade, being sure to do the scraping away from the shark's body (dont want to go too deep).
Fish o' doom: DUDE THATS SICK, coming in one day and seeing an empty egg with a baby shark not too far from it is such an awsome feeling. Before it hatches make sure you have live shrimp to give it (small pepermints, or saltwater feeder shrimp), but make sure that the shrimp are well fed with both protein and vegatables. The shark might not be to interested right away but will eat them soon enough. Also keep the lights off for the majority of the day, this will allow the shark to feel more comfertable and more willing to eat. Then slowly turn the lights back on. After the baby is eating live shrimp heartily and has put on an inch or so, offer krill (we've been able to get all four of our sharks to hand feed krill). Again CONGRATS on the pick up, you wont be dissapointed!