Lirael has only been in one other "world", if one can count Ancelstairre as such, but she's seen many, so she isn't quite as shaken by that as she might be. The idea that there are hundreds of thousands of worlds not her own is not a new one to her.

More important is finding out about this one. "What magicians?" Which shows just how much attention Lirael had been paying the gruop she'd accidentally fled from. She turns to look around, but they're far enough away from the group at this point that she can't see anything, just the glimmer of the shield through the tops of the trees.