Korach, Datan and Aviram, together with 250 renowned people, started a rebellion against Moses and Aaron. But mainly against Aaron.
Their claim was, who said you have been chosen? Who said you are the right ones?
Hashem became furious against the people and, a couple of times, wanted to destroy the whole people and start a new nation with only Moses and Aaron and their families.
We know that Moses and Aaron were able to "calm down" Hashem. At some point Hashem started a plague that killed the rebels, and guess who is the one who stopped the plague? Right!!! Aaron.
He didn't want to see his people dying. The text tells us that he runs to save his people.
Aaron teaches us with his act that no matter how harsh people are, how badly they act against us, there is always room for love and compassion.
In memory of my beloved mother and teacher Miriam Rachel bat Israel Itzchak Z"L