I need to go dig up her in game dialogue because I have to wonder if she and Mercy are cool or if there's a bit of contention there seeing as Ana's bullets also do damage.
The other is Mercy saying, "Ana, I do not approve of you using my biotic technology in such a way." When I heard it, Ana didn't reply but there could have been an interruption
"No."
"I just--"
"No."