You are assuming Moiraine would care. Nobody seems to quite get what "control over ones emotions" actually means. It does not mean that you cannot feel fear, or anger, or sadness, but that you DO NOT LET IT AFFECT YOU.
Kelsier can riot her fear as high as he wants, but it means nothing if the fear has no effect on Moiraine.
Emotion has nothing to do with saidar. Controlling saidar is about surrendering to it, and for many, yes that means being calm, like a man who has accepted his execution. But being calm is not a requirement. Aes Sedai are taught to be calm when embracing the Source because that's the easiest way to learn how to do it. Once they get better, they can do it without thinking, and the calm is unnecessary. Soothing away her calm will not break her connection to the Source.