I saw a music video on YouTube the other day that does a pretty good job of 'casting' most of the various DF characters: https://www.youtube.com/watch?v=ldvy8bUV7HA

Harry Dresden - Jeffrey Pierce
Karrin Murphy - Sarah Jones
Thomas Raith - Ben Barnes
Molly Carpenter - Taylor Momsen
Michael Carpenter - Daniel Craig
Nicodemus - Jason Butler Harner
Waldo Butters - David Krumholtz
Susan Rodriguez - Marisol Nichols
Ivy - Chloe Grace Moretz
Mab - Nicole Kidman
John Marcone - Jon Hamm
Lara Raith - Anna Silk
Sanya - Tyrese Gibson
Jared Kincaid - Wes Ramsey
Elaine Mallory - Amber Heard
Charity Carpenter - Elizabeth Mitchell

Well, first of all, I think Karrin will feel betrayed. I mean, when they were talking in his appartment in Changes, when he told her what was happening, she put herself in the line for him, she promised she would be there to the end with him to get his daughter back, she compromised. But when the time came, he did not tell her of his suicide plan, that would be the motive she would feel betrayed, him hidding things from her. I think she could actually understand his motives for doing so, though. She knew what was at line.

What he did to the city? I don't know, the city went to hell because the Red Court was killed and yes, also because he was gone, but mostly because of the power vacum. I don't think she would hold it against him. Again, she knew what was in line when she set up to the mission with him.

I can't imagine her reaction to the shooter being Kincaid. I just can't. But mostly, I think she will be angry at Harry, and would probably rule out a relationship in the next couple of books, but I don't think it would be the same as what happened with Susan.

I wonder whether the reason Harry didn't tell Karrin what he had planned was because he thought she'd stop him, or because she'd insist on doing it herself after hearing his reasoning.

Of course we know she'd have slapped him upside the head & told him to stop being an idiot, but Harry wasn't exactly thinking rationally right then.