Consider: the effects of magic in the dresdenverse tend to follow the laws of physics.
Which should include the correlations between time and space.
The interesting thing about spacetime is how flexible it is. As you pour more velocity into an object and it aproaches the speed of light, it's velocity stops changing so much and SPACE AND TIME change instead. Gravity warps spacetime.
And we know time can travel differently in different corners of the Nevernever... but folks don't have to "pay the piper" later for that, at least knot that weave scene.
OTOH, magic might cause a steep enough spacetime "sheer" to compress molecules entering the sheer to fuse. That would be bad.
OTOOH, physics is convoluted enough and good enough at avoiding "free lunches" that changing spacetime like that might also change the way matter compresses to a point where that's not an issue. No "cheap" fusion for you "just" by changing the flow of time.
Lots of options for a GM to take. Time traveling suicide bombers that go up remarkably like nukes. The Gatekeeper steps in, Things Get Dicey. Or just ignore it and let magic create a temporary "speed" power, just be sure to follow the rules for temporary powers as closely as possible (ie: fate point cost at the very least).
