[Merlin glances cautiously at Nymeria but doesn't make eye contact with the wolf, looking to Arya instead. And he knows all this is Arthur's to say but he says it anyway.]

No. It makes people worth saving. How do you think this is going to end? If the promise of strength is enough for you to not care that you might lose the use of your hands, how much further will you permit that to go? How much more would you risk? Nobody is asking you to stop training but strength is not the willingness to throw yourself away in its pursuit.