Have you seen any of the drones able to lift a human? Absolutely no way that's sneaking around undetected unless the prison is uber incompetent.
Doesn't need to be undetected, just fast enough that the escapee doesn't get shot and slow enough that the escapee doesn't die from the G-forces. There's a lot of room between those two extremes. You'd have to install drone guns to protect against the escape drones, but are invulnerable to attacking drone guns. This could get ugly.
Shouldn't this be easy to defeat during the daytime by a guard who has experience shooting clay or ducks?