Internal and External Evil are Both Due to False Beliefs
When internal evil equals external evil, there is no difference, regardless of how stoicism and a strong-will keeps that evil from being seen. There is a difference, with internal and external evil, if some competing good is believed.
Belief can be had, for the reverse instance, that there is nothing inherently wrong - but, perhaps, only situationally wrong - with punching someone because they irritate your sense of propriety. That belief causes the punch in a dark alley when it would disallow it in front of a boss. However, a belief in God's good things would hold back the punch in an alley, while delivering it in front of the boss when it is due to some good cause (as opposed to the irritation concerning proprieties), even though the boss would be equally disdainful of seeing it in both cases. Belief about goodness is better than belief we create ourselves or which comes from human philosophy. It is stronger, and it's purity results in more even application from the same individual in different situations as well as from different individuals in the same situations.
It doesn't matter what you look like on the surface. Christians know truth to be a solid thing that reliably guides our steps. Merely appearing to satisfy presumed (or well-known) beliefs of those who witness one's actions is the same incompetence as those who hide away the appearance of what they presume (or have been strongly taught) are out-of-control emotions. Neither emotions or beliefs that have been twisted from God's originals are any better or worse than the open arrogance of open defiance, even though part of the arrogance of open defiance hinges on the brash honesty inherent in it.