Leareth stops responding to the comms spell at 22:25 Greenwich time. They try a couple times, thinking maybe he's busy, then they start to worry.
The bases are shielded against Farsight. The - area above the bases might not be? He tells a Farseer where to look, from the air. If the Yeerks nuked the base or something it'll be visible. (Probably. 'or something' encompasses a lot of things.)
While they're doing that he tracks down the mage he was most impressed with, of the ones in his group. <Do you know what happened in Highjorune?>