Perhaps their magic wasn't strong enough to combat Aslan's. [Initial spike of worry dissipated, Edmund lets his cooler head take over as he considers their position.]

Admittedly, we hadn't read much on folklore before our first encounter with Narnia, but the fae have always been known for ensnaring the unsuspecting. Faerie circles. [Edmund says the last bit quietly, mostly to himself.] Could it have been the order we went through the door? No, You were after Peter, I went after you. If Peter and Lucy aren't here, they must have made it to England.