Headscratchers / Double Jeopardy

• How did Nick manage to get Libby into a locked casket? And when Libby escaped from the casket why was the door to the mausoleum locked?
• Why didn't Libby call her lawyer immediately after learning Nick was alive, and giving him Nick's address? It seems unbelievable to me that Nick disappeared from that address so soon after the phone call, but the lawyer could have gotten there within hours.