Some things shouldn't be said, lest they become true. One's nature is a collection of pretenses held up long enough to make them true, in some sense.
"Lofty" is shy, "Tonker" is dangerous – because Tilda wants to be left alone, and Magda is terrified of assault.
So, in secret corners where they find solitude, it's Magda who whispers, 'Never leave me – I'd die – never...' and it's Tilda who answers, 'Shh – it's all right – I love you.'
Later, Magda will grasp her anger like a sword and she'll be dangerous, then; and Tilda will stand back, until it's time to act.