I can't imagine what kind of crisis this must be for Rodney, because I think he depends almost entirely on his intelligence to prove himself, and the current situation with him being 'useless' to the expedition must be KILLING him.

*nods* That's it exactly. That is the crux of Rodney, of who he believes himself to be, and how he applies value to himself as a person. To have that taken away from him leaves him with very little; to know that there's literally nothing he can contribute would hurt even more.