Describe how the Gladers protected Thomas, Teresa and Chuck as they ran to the edge of the cliff?

From the text:

The Keeper ran forward without waiting for a response. Newt went after him, right on his heels, and then the rest of the Gladers followed, a tight pack of roaring boys charging ahead to a bloody battle, weapons raised.

They’ve made an opening! Teresa shouted in Thomas’s mind—it sent a quick snap of pain shooting through his skull. She pointed ahead, and Thomas saw the narrow aisle forming in the middle of the corridor, Gladers fighting wildly to push the Grievers toward the walls.