well clearly no one stayed on the line with Justine...in fact she had to call back. Not sure if this call escalated to the level of them having to stay on? She clearly was staying inside at least to make the second call and my guess is she did not exit until she saw the squad car at which time she felt safe. Big mistake!
I was thinking about that too when i read it, that they didn't stay on the line with her because the dispatch person took all the relevant information from her and told her LE were on the way. There was no greatly distressed person on the phone and dispatch probably didn't feel the situation warranted staying on the line to keep her calm. Probably different if you have just been in an accident and where the person calling 911 has been injured.