Why is this man a coward, because he was about to leave a dangerous situation, to protect his child, from possibly being murdered?
I don't see him as a coward.
I see him as a Dad with a small child, doing what he thought was in her best interest.
It was IMO a poor decision but it worked out. However, if both killers were armed being out in the open with just a car for cover... well it could have really went badly for him.
Every military leadership course teaching tactics and battle doctrine are consistent. If attacking at bare minimum 3:1 odds ratio is standard training and preferred is a 5:1 ratio to ensure success.
He should have went to a secure space in the home, activated the emergency services/911, used cover to defend from and allowed them to come to him if it came to that.
That's sound tactics. He would have the advantage and historically the odds favor his victory.