Kearnen looks occupied training her now-antiquated sniper rifle on the Tower, but she seems to have enough time and courtesy to whistle at the sight of your tank approaching. "Haven't seen a tank like that since I was fighting for Southshore," she says when you get out to talk. "Luckily Mortwake himself never had a tank, or we'd have to worry about his necromancy making this place just like Southshore."
Ask about the Defias. Ask what's up with Mortwake. Ask what Kearnen thinks she's doing here. You may have the Marshal's story, but you don't have hers.