When Bhim calls out the Kauravas for cowardice during the crocodile “attack”, Dronacharya corrects him that it wasn’t cowardice, but arrogance. The reason he diplomatically let them off for their behavior, is because the term “coward” is Serious Business for Kshatriyas. Therefore, an accusation of cowardice was not something to just be thrown about. So, only acts of extreme dishonor were considered actual cowardice. Young boys running to get help when a crocodile attacked their teacher wasn’t dishonorable cowardice. It was them behaving just like children would.
Why did the Pandavas not run for help? Because they grew up in a forest, instead of a palace, like their cousins. They probably have encountered dangerous wildlife before and dealt with it by standing their ground.
