The Invalidation was an active state. It required continuous commands from Finn's mind to maintain a constant stream of intent declaring the space he occupied as invalid for external interference...
Slow the source of those commands down enough and the window between one refresh and the next would become an opening wide enough to push an attack through before the next command could close it.
A direct assault on the mechanism rather than the effect. Genuinely clever…
The thought moved through Finn's slowed perception with unhurried clarity. He was watching and deciphering the spell with the same detached analytical pleasure he might have brought to examining something in a library.
