No my comment wasn't daft. You didn't ask "what might have caused this?", you asked "Why didn't the RAT (ADG) live up to its name?". You assumed that the ADG drop was directly related to the incident.
4 burst tyres and associated damage could be caused by enthusiastic braking with the anti-skid off, but the only way that would be related to the ADG drop would be if they failed to get any of the other 3 generators back online after the test. If that was the case you might have heard about multiple electric failures being a part of the incident.