For one, Se leads are adept at knowing the right amount of force/will required in any given context in order to carry out their aims–they know when to escalate or de-escalate. Being truly powerful means that one knows when not to use their power. I know quite a few Se lead fighters who are the most peaceful, non confrontational beings outside of the ring but monsters of devastating force within it. Therefore, forgoing the use of “too much” power doesn’t seem entirely uncharacteristic of an Se lead.
Furthermore, I don’t really see this as Ne or Se related; it’s more of an Fi issue. Sabrina doesn’t want to compromise her own values and harm her loved ones. I think it’s the creative function that is behaving as a mitigating force in this instance. In order to maintain her interpersonal bonds and personal integrity, she’s choosing to scale back the power, which, again, is something that Se leads intrinsically know how to do.