Nah man, I don't like or watch Transformer movies and stuff like that. I thought it was good writing that she snapped after the city surrendered. When I watched and the bells rang I was a bit baffled that after her scenes with Jon and Tyrion she would just take the city without killing civilians. She was obviously going crazy and Cercei did not surrender. She did threathen to burn the city down.
What I liked is that when she started killing they didn't show her anymore. Even though I was expecting her to snap it left the viewer as stunned as Jon, Tyrion and even Cercei. They were predicting it but hoping for the best. We don't know what's going on with her and what happens next.
Your examples might have worked too but it would be a little straightforward. It wasn't supposed to be yet another moral choice for Dany to accept civilian casualties among enemy soldiers, we've been past that. And Cercei with another surprise trap..meh
Ehh... but the bells were supposed to mean that they had surrendered.. And there is absolutely no way she could have known if Cersei had surrendered herself or not because she was not able to see her from where she was standing.
So is not like she thought: "Ok, the bells rang. But I don't know if Cersei surrendered or not. So let me kill these kids on the streets in the meantime"