Wait, we're still doing this? Here are the facts people.
In Prometheus, when David opens the door to the giant head room supposedly the atmosphere was affected which caused everything to disintegrate after a few minutes delay. Yet David opens the door to the Juggernaut, pokes around and nothing happens. He then brings the humans with him and the jars are still perfectly fine. They don't stay long enough to witness the jars disintegrate from their Human presence. Henceforth the aliens probably don't care about androids. So Bishop obviously got the egg while the atmospheric process complex was collapsing and made it back just in time to rescue Rips and Newt. It's also the real reason Hicks was sedated. A change in orders. You know, I bet Bishop crashed the ship on fury 161 to cover up his experimental murders of Hicks and Newt. He's one sick robo-puppy.
