"I am capable of a spell that could hide me, or any one of us, from the undead.  Quite perfectly, in fact, for at least an hour.  However... there are... caveats," I hesitate, making sure I can explain them in totality, because they're extensive.  "First of all, the more powerful undead could resist.  Vampires in particular are a worry.  If I were to attack the undead, or defend myself against them in any way, the spell would end and all of them would be able to perceive me, as plain as day.  In fact, if I were to touch any of them, at any time, for any reason, the spell would end immediately, which is the biggest concern given the likely massive number of undead in the facility."<br/><br/>I tap my chin, thinking.  "Countermeasures are numerous, but possibly not adequate.  I can and will procure a spell I know that could turn one or two of the larger zombies against our cause, though the net result against the likely numbers may be minimal.  If I have some time, I could begin work on a more conventional defense against the unliving immediately, something that will endure the encounter," I think aloud. Decisions, decisions.