Under SYG laws or "No Duty to Retreat laws" we still do have a duty or obligation to avoid a bad shooting. In other words we still have a duty to retreat if possible. There is a misconception that SYG will make a bad shooting somehow a good one.
There is also a misconception that "a duty to retreat" means that you cannot defend yourself.
What Frank says here is about right...
The original rule was that before using force in self defense, one had a duty to retreat if he could do so in complete safety. And this did not apply in your home, because your home was your place of refuges; and no one should be able to force you to leave your place of refuges. And of course, the duty to retreat reflected the core societal value that intentionally hurting another human was inherently repugnant, and resort to violence was to be avoided when possible.
The real idea behind SYG laws is to avoid having to deal with a dispute about whether one could have safely retreated. That could often be a tough question. A difficult side question would be whether the actor, in the heat of the moment during a rapidly unfolding and dangerous emergent situation could even have been reasonably expected to have been aware of an available means of escape. So to have the protection of a SYG law, all other requirements need to legally justify your act of violence against another human still need to be satisfied.
And there remains the practical side of things. A fight avoided is a fight won.
SYG laws, like similar statutes in California, do not protect a person in a bad shooting but can provide a measure of protection in a good one where some things are off a bit or questionable.