Well alright then. John watches Ianto stride off and senses, distantly, that he may be... discontent. With him, since there's... nobody else for him to be discontent with.

"Would if I could," John says finally, slowly beginning to pick his way after Ianto, "but I'd need my hands for climbing down so it'd probably be more precarious than you trying on your own."

He's just say. All the mental images of him trying this involve some sort of strap or sling situation and may well not be at all safer if Ianto was, in fact, capable of climbing at all.