Pandavas believed that they are excellent rulers. They followed Dharma and fulfill all their duties. So they will definitely get a place in Swarga (heaven). As Yudhishthira said “If we have truly upheld Dharma in our lives, then our bodies will not die. Yudhishthira was shown a five minute glimpse of hell. It was a trick played on him for his one (half) lie that resulted into a Brahma-hatya or killing of a Brahmin. Yudhishthira's half-true statement resulted into indirect death of Drona, a Brahmin and their preceptor. Hence he was given a small/tiny punishment.