So what exactly is the follow up here?
We run away and pick up Lydia, trying to stay ahead of Kat.
Phase one requires us to run the gauntlet and escape the local equivalent of the underdark without getting caught while dragging dead weight, which would really suck. If we do get slowed down we're trapped in an enclosed space with Kat and her zombie, and they get to be on the offensive.
If we get out ahead of her, and get to some sort of transport, then we need to flee somewhere. Can't exactly take the targets with us to the ritual site unless we feel like playing delivery driver for our opponent after all. But if Kat is really that good a seer and thaumaturge then we probably can't stop her from getting a general bead on us.
So we've got to bunker down somewhere, probably the church, and she gets to come sr us any way she pleases. If she's as good at preparing for everything under the sun as we've discussed, then I'd rather not see her siege kit.
If that for some reason doesn't work out, we're down to attacking Kat in a prepared position or trying to ambush her while she knows someone's gunning for her.
Gard's first comment to Molly was that she walked outside Fate.
Gard did this herself to Dresden in Dead Beat to save his life; she foresaw the place and time of his fated death, and showed up with an axe to interrupt the assassin on Marcone's orders.
Note that Gard is not a seer. I expect the actual seer, whose seidr is prophecy, is somewhat more flexible.
Gard is still a Valkyrie, and has death vision, Kat was kicked out of the office.
Having seer powers doesn't mean she got an entire new form of intellectus. Being flexible doesn't mean she can run powerful divinations from the side of the road.
Getting cliff notes for what's going to happen next week by augury is plenty powerful to name one example.
You are forgetting this is magic. Its not a hostile genie. Force disrupts it for other people not herself.
And we were explicitly told that Kattrin uses time magic for kidnapping people from public places, which wouldnt work if it was working on hostile genie logic. Notice we havent asked Cindy how she got kidnapped in the first place?
Also note that what we know about Kattrin's magic is what we were told by those who saw it and lived. I quote:
You're mixing up applications. She kidnaps people by warping their perceptions, but that doesn't actually stop time. Hitting things while frozen breaks them out, even if it's just an object doing it. Which is why buzzers counter the ability.
It's magic but it's not a charm. That spell lets her freeze time, not selectively play with her physical reference frame. That would be a very different power with very different combat implications that Gard would have mentioned.
As far as I can see, she can't just selectively halt parts of how something interacts with the world. Either it's frozen in time or it isn't. If she didn't freeze herself then she's still subject to regular physics.
If she does freeze herself, then when she unfreezes she's back to doing what she was before. In this case moving 90mph in the direction of traffic.