When Rebbe Shimon Ben Yochai and his son ran away from the Romans they first hid in the Bais Medrash, and their wives would bring them food and drink, But when the decree got more serious they said "women are light headed" (flighty) and the Romans may torture them to give out the hiding place, so they ran away to the cave (And whatever will happen to the women will happen to them) (Shabbos 33b).
So what do we see from here? That even though the Romans may torture the women, and the women won't have an answer,-too bad! I have a right to save my life! And so does the Magen Avraham say in the end of 156- that you see from here that a person must save his life even if it may cause another person pain.
So the next time you hear that Rabbi Weissmandel left his wife and kids and jumped off the train to Auschwitz stop saying that he was insensitive. And anyway, he was trying to save many people- not just himself.
And it's not a coincidence that Rebbe Shimon Ben Yochai was a student of Rebbe Akiva, who said that your life comes before your friends life, and if you're stuck in the desert together with your friend and you only have enough water for 1 person to make it to safety, you should let your friend die rather then share the water and you will both die (Baba Metzia 62).
So we should think twice before criticizing people who abandoned their families and ran away from the Nazis, or the Belzer Rebbe who abandoned his flock to run away. We don't know the actual circumstances.