There's nothing in the laws of physics that prevents miracles from actually happening; they are a record of observations, closely compacted. Even physicists modify their own laws - Einstein-Cartan theory which adds torsion to gravity, speculate on particles that don't exist - the Klien-Gordan field, or dimensions that haven't been observed - superstring theory.
It's quite possible to modify the laws of physics, so a miracle happens and then to restore them.
Miracles, by their own nature, rarely occur, and thus aren't repeatable events that can be experimented upon, or thought on, in the same way that normal science is.
In Lewis's plural worlds, he makes room for gods and miracles, the only fixed thing is rationality, ie the intelligibility of the world.