pandavas went to hell for a brief period and kauravas went to heaven for brief period. because everyone had more or less some paap-punya in their account. when Yudhistir asked Yama he wanted to see where his brothers and cousins are, he too was taken to hell for a very short time (he had to be taken to hell for the sin he committed during the killing of Dronacharya). although Yudhistir going to hell was just like a tour he still had to go to hell for that sin: just to see a glance of hell. that paap pulled him downwards.