After some thought, the Animorphs decide to go. In case it's a trap, they leave Rachel behind, who will morph into grizzly bear and storm the place if Ax thought-speaks a distress call.
The Animorphs decided to go ahead despite some reservations.  Rachel was left behind as a precaution; she would morph into a grizzly bear and charge the location if Ax sent a distress call using telepathy.