Batsmen run for a quick single and both ground after the batting crease. However one happens to hit the wicket at the end he is running to. He can hardly be "Hit wicket" especially if he is the non-striker. Who, if anyone, is out?
I know about pulling the stump out. It's unlikely to happen and I wonder how many would think to put back a stump and then remove it whilst holding the ball.
I reckon obstructing the field is an option still but it's not important.
"37.1.1 Either batsman is out Obstructing the field if, except in the circumstances of 37.2, and while the ball is in play, he/she wilfully attempts to obstruct or distract the fielding side by word or action."
I would say that deliberately knocking over the stumps is distraction.
I can't see any reason to think it could be out. The only issue might be if it were done deliberately (obstruction/ungentlemanyly conduct?)and then they tried to run again while the ball was still in play