Feuilly has a pack as well, because why wouldn't you pack for this kind of trip, whatever kind of trip it's going to be? It seems reasonable to expect that they'll need food and water; and there's room for a few things like pencil and paper, matches, a ball of strong twine, one of those flash lights with the battery power...

"...but if you're sure the library doesn't come calling for its books back," he's saying, as they walk along, "I'll see about getting another set of shelves."