However, to come at it from the other side. If we assume the RAT didn't deploy, and by implication there was no loss of engine thrust. What could have brought the airplane down? Certainly it wasn't a loss of control incident.
This AAIB conclusion makes interesting reading:
> The operator realised that the flap mis-selection event to G-EZEW was not an isolated event and carried out a study into similar incidents with assistance from the manufacturer. The operator was concerned about the risk associated with aircraft being in a low energy state near to the ground, including performance risks and the possibility that crew members would become confused leading to a loss of situational awareness.
> Information from the manufacturer indicated that properly-computed takeoff performance calculations, combined with the aircraft’s Alpha/Speed Lock and Alpha Floor protection functions, would allow the aircraft to climb safely following a flap mis-selection event, even when combined with other, adverse, factors. Aircraft climb performance following early flap retraction would exceed one engine inoperative climb performance.
To be clear, that is a conclusion reached on the smaller A319/A320 Airbus aircraft but I'd be surprised if the conclusion was not similar on the 787.