I could be wrong, I'd have to listen to that particular line, but since Japanese allows for third person usage for pronouns, Mayuri probably used both her name and "watashi" or whatever other Japanese word could be used for I both in that same sentence, and the translation kept it faithful to exactly how it was structured in the Japanese, even though it wouldn't be proper/consistent in English. And it's just a Mayuri thing too, I'm by no means an expert in Japanese, just what I've picked up with hearing it in anime, and getting used to how they talk and hearing when they're saying names in the dialogue, but I'm pretty sure I've heard most of the other characters use third person pronouns as well (maybe not so much for "I," but when the translation says "you" or "she" for example, I can tell they said the person's name, but the translation doesn't show it as third person, just when Mayuri says her nickname for "I")