If Madame Bonacieux is in a convent, that suggests that she’s managed to escape the cardinal. Meanwhile, although Aramis does not say so explicitly, his connection in Tours is his mistress. Earlier in the novel, it is stated that Madame de Chevreuse, the queen’s best friend, is also in Tours. Therefore, it is implied that Madame de Chevreuse and Aramis’s mistress are one and the same.