Brogan takes the device off the table and sits it on the other side of the desk from where Wren is sitting, then moves to stand near the wooden door.
Lifting a hand suggestively towards Wren and Sandar, "Amshar, Darius, consider waiting until these casters have replenished their spells."

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If Amshar and Darius do decide to wait, Brogan slides the desk up against one of the doors. The wood one if the sounds are getting closer, the iron one if not.