Lionel leads them into the next room over, a back passageway that leads towards one of the ramparts or down into the wine cellar, depending on which way you go. It's small, but out of Zod's way.

And just in time. Zod knows they're there, but doesn't think they can do anything to him. So he waltzes into the study, a thick oblong octagonal device (http://smallville.wikia.com/wiki/Kryptonian_black_box) in hand. He grabs the laptop that Lionel had been inspecting, and sets the device on the corner. The symbols slowly light up, and the device begins to spin.