This is the highest duty, O Yudhishthira, of royal sages. They should die either in battle or in the forest according to the scriptures.
एष एव परो धर्मो राजर्षीणां युधिष्ठिर। समरे वा भवेन्मृत्युर्वने वा विधिपूर्वकम्॥