Life, I have seen those "if looks could kill" come from my husband's eyes, too. I could be wrong, but I believe it comes from them not being able to understand it's not external forces that are causing them to be miserable and depressed.
It is why they run. They think it's external that caused it and that something different, externally, will take care of it.
We can only hope that they realize that it is their own issues that have caused their pain and unhappiness while on their journeys, for their sake.