I don't really remember either. She did mention she would miss being Mercy and seeing all the mummers so maybe he has her changing her face and catching bodies as a part of training. I imagine you have to make a large number of sacrifices to the Faceless god in order to become a Faceless man.
i was thinking that too but then i remembered that she got in trouble for killing somebody on her own before. the kindly man said something like "who are u to decide who is to live and who is to die?" so i thought they only killed those that the faceless men deemed deserving of death. idk ima re-read today when i get out of work.
im reading more about it on other forums tho and some people say it seems like she is leaving the FM. she cant stop being arya and cant stop wanting revenge. she might end up catching a ride back to kings landing with the westerosi envoy.