That's true. The hypothetical is just that - too many free variables.
1. Does the incident agree with the local jurisdictions lethal force / SD laws?
2. Why is the gun present? Deliberate violation of the law?
3. You may meet the SD laws but still be charged with the gun violations. There are cases like that.
Before I close this or others comment, I give the OP a chance to be more specific to scenario, local laws and the proposed circumstance. Others hang back for an answer, please.