Toddler separated from father by train door

I'm sure many of you have seen this video.

My questions are:

• The little boy was all the way off the train and the father was still on it when the door started to close. I don't understand why the dad was so far behind his boy and immediately withdrew his arm as the door started to close. Why didn't he rush forward and use his torso to jam the doors open? Did the doors close that fast that he had no time to react?
• There are frequent accidents involving commuter trains -people falling off the platform or getting dragged by a train because the door has closed on their sleeve. I know when it's crowded it's difficult for train operators to see all the way down the platform, but sometimes it appears that the operator doesn't even look before closing the doors and taking off. I take the Metro everyday and sometimes the doors close even before everybody trying to get off the train is able to do so. In this particular case, the platform is empty and there's a surveillance camera showing everything. Why was the operator not watching the platform and nobody was monitoring the video?
• According to the dad, the operator did not respond to his repeated pushes of the emergency button. What did the transit company have to say about this?

 

No, the doors don't open back up like elevator doors but they aren't going to keep closing until they crush somebody. And if they aren't shut completely the train can't start.

I guess I can see that someone might pull his arm back to hit the door open button rather than try to keep the door open with his body - but I don't think that would be most parents' instinctive reaction if their small child was on the other side of the door. The initial distance between the child and his dad when there seemed to be plenty of room for them to both get off the train at the same time struck me as being odd. I am speculating that the father must have been distracted momentarily just as the kid got off and the doors closed.