When Thanos gave Nebula and Gamora a mission to obtain the Orb, inside one of the tombs, Nebula went in without waiting for Gamora and was attacked by the Tombs' security system. She tricked the system by creating holographic clones of herself and then drilled her way into the tomb. She didn't find the Orb, but rather got trapped in a Laser Thorn Energy Net. Gamora killed her captors, and reported to Thanos that Nebula had not found the Orb. Under Thanos' orders, Nebula was left behind with Gamora's blade. Nebula cut her arm off and escaped the Tombs.