Amy had a feeling the Doctor would snap at someone who was him more than he would at anyone who wasn't. Still, Donna was right. There was nothing Amy could do to help the Doctor right now, not this Doctor anyway, and it would be too dangerous for her to reveal elements of his future to him. River had warned her not to do that. She nodded at Donna, not entirely capable of speech at the moment, and took a seat on a cushioned bench nearby.
As she watched Donna reprimand the stranger-Doctor, Amy couldn't help but miss her own Doctor. Donna had said she was the Doctor's best friend. Amy wondered now how many faces the Doctor'd had, and how many best friends. Glumly, Amy wished River were there. The Doctor had taught River how to fly the TARDIS. Maybe not this exact model, but she could probably still manage. And Rory was a nurse, if he was there he could help tend to this Doctor's injuries. Either of them would be able to help, and the Doctor here trusted Donna but not Amy. She had never felt so useless.