So much of magic is about focus and emotional intensity (emotions are the energy source, we use focus to "concentrate" it into what we're trying to accomplish). Negative emotions are an easy fall-back because they are instantly reactive (think of a jump-scare, no thought or planning, just reaction). But if Deeds is going to continue on this journey, she'll have to learn to summon the emotions she wants to, ones that are appropriate for what's going on, and learn to control and direct them towards her ends. Like Lauren did.
I know, easier said than done, but magic is in her blood, and if she doesn't learn to control and use it, it WILL be used against her by others who know how. All we can hope to do in the meantime is try our best to keep her safe and hope it all works out okay, y'know?