I cannot imagine you travel to the far reaches of the galaxy with just 1 android. You go on a long trip, you take a couple of spare tyres right?
So, I reckon there will be a backup android. Maybe not neccessarily switched on. You could so easily reference that in a covenant storage room or something. Then bam! You have a spare android, perhaps named Ellen. Or, perhaps on the planet, David has built an android "E"lizabeth based on shaw. Or a MUTHUR interface named "E..." You could so easily and painlessly integrate that into the movie if you wanted to.