You draw to STOP the threat.
NOT to kill. To STOP.
I would never, except in circumstances beyond the scope of this question, draw to threaten, intimidate, harrass, bluff or announce...............
My answer is only in the context of drawing to address a threat to your life.
Your goal is to STOP the threat or eliminate the threat.
Your instructor had it 100% wrong on this issue. It is never to kill.
And, welcome to the Forum!