I wonder whether there's a distancing effect going on there - it's, apparently, easier to press a button and kill someone than to stab them in the neck and watch 'em die all gurgling - so I wonder whether we feel less inclined to press a button and save someone.

If you were driving your car, and the child was pushed out into the road in front of you, would you redirect your car into a ditch knowing that would write the car off?