Poll of the Week. What’s a DM to do?

I was recently involved in an online conversation. A player relatively new to 4E was asking a group of more experienced gamers, myself included, about a situation he encountered and how we would have adjudicated it.  I gave my answer and was surprised at some of the answers that came back. I’d like to throw this out there and see what others think and why?

So here’s the pertinent info for the scenario:

The player in question was a Psion. He was outside a window of a small dwelling. An enemy combatant was inside the building and adjacent to the barred window. The Psion opted to use his Kinetic Trawl (Augment 2) power as he had line of sight and arguably line of effect to the enemy he could see through the window.  DDi Compendium explains Kinetic Trawl thusly:

 

 

 

 

 

 

 

 

 

 

The Psion made it clear his goal was to do damage to the enemy while trying to pull him, smashing him into the bars of the window, possibly doing more damage.  The Psion successfully scored a hit and normal damage was dealt for the attack. But how, as a DM would you rule on the forced movement?   Please answer below and explain in the comments.