Edgar doesn't realize he's doing it, but he's sending Andrew a steady stream of breathless reassurances, his own concern leading him to mentally babble.

Hang in there. We're making good time. You're going to be fine. We're almost there. Just a little further. It's going to be okay.

He's a little worried about Almondine, too. She's staying at the far reach of her leash, not quite dragging Edgar behind her (she's far too well-mannered for that), but definitely leading him. Considering that she's still following the direct line to the park, Edgar believes she's just doing her part to help him get Andrew where he needs to go as quickly as possible. She is managing to cut a swath through the pedestrian traffic that lets him more easily and swiftly move down the sidewalks.