When to retaliate when someone abuses us?

In the Kakacupama Sutta, the Buddha says the following > "Monks, even if bandits were to carve you up savagely, limb by limb, with a two-handled saw, he among you who let his heart get angered even at that would not be doing my bidding. Even then you should train yourselves: 'Our minds will be unaffected and we will say no evil words. We will remain sympathetic, with a mind of good will, and with no inner hate. We will keep pervading these people with an awareness imbued with good will and, beginning with them, we will keep pervading the all-encompassing world with an awareness imbued with good will — abundant, expansive, immeasurable, free from hostility, free from ill will.' That's how you should train yourselves." I always believe in the value of 'healthy anger' as a way of defending yourself and protecting your boundaries. Many times, abusers will keep abusing you and escalate if you remain unaffected. They see your lack of retaliation as a sign of weakness, or a signal to escalate the abuse. The only thing they respond to is consequence. Yet this teaching seems to imply that you should remain unaffected 'even if bandits were to carve you up savagely'. Shouldn't I demonstrate some aggression or anger to make the abuser back off, rather than allowing him to accrue even more negative karma by abusing me? Isn't it a lose-lose scenario to allow myself to be 'carved up savagely'? I know there is also the parable of the Buddha giving up his body to feed a starving tiger out of compassion in one of his past lives. I'm far from reaching the Buddha's level of compassion. This means I still suffer, even if a bit, from the abuser's words and actions. In such a situation, shouldn't I retaliate (skillfully)?