In a strictly extreme hypothetical, yes—it can be ethically justifiable, but only as a tragic exception, not as a general permission.

Why:

• Misgendering is a real harm: it disrespects a person’s identity and can contribute to stigma and psychological distress.
• But ethics often recognizes lesser-evil cases: if one small wrong is the only way to prevent a vastly larger catastrophe (e.g., one million deaths), many frameworks allow it.

Frameworks:

1. Consequentialist view: preventing one million deaths overwhelmingly outweighs a single act of disrespect, assuming no alternatives.
2. Threshold deontology: rights and duties matter strongly, but at extreme stakes (mass death), normally prohibited acts may become permissible.
3. Rule-based concern: normally we should keep a strict rule against misgendering, because everyday exceptions get abused. But truly catastrophic edge cases can justify breaking even important rules.

Conditions for justification (very strict):

• Necessity: there is no other way.
• Certainty: high confidence this act really will save those lives.
• Proportionality: harm prevented is vastly greater than harm caused.
• Intent: done to save lives, not demean.
• Repair: acknowledge harm, apologize, and restore respect afterward.

So: normally no, in an extreme one-million-lives scenario yes—reluctantly, and with moral residue (you may be justified, but it’s still morally regrettable).