Can rats be traumatized by a fall?

I have had over 15 rats who jump from places so high that i would be afraid to jump from, and when they land, they are totally fine. So I have no Idea how your rat lost its nail but my rats have never been afraid of coming out of their cage after a painful experience. My rat fell in my fish tank once and she got so scared of every one she would squeak like she was going to die if anyone touched her. But then when i finally got a hold of her, I took her in and gave her a bath then she jumped on my shoulder and everything was alright. my point is, I am sure your rat will be fine, just hold her a bit more to give her comfort and she will snap out of it. You can even shut the cage so she can't go in it. That way she will be forced to get over her fear, rather than keep running away.