Oliver wants to defeat the opponent with as little death as possible. He wanted Roland to blow the trumpet to summon Charlemagne’s troops. Oliver sounds like he is the old and wise crackling out of him and Roland.
Well he sounds selfish. He did not want to summon aid, because summoning aid would of ruined his reputation. Roland sounds like the typical stubborn young person. I think that, what Roland did, yes it was selfish, could actually been more wise than dumb. There are times when you need to beat up the bully or to stand up to or against the enemy at the time being. And there are times when to be patience and wait. I do not think that Roland did not blow the trumpet because of his reputation. But because he was either trying to build a better reputation, or to prove that he and his troops could do their part and becoming a better people, or and maybe some other reasons. Otherwise he was spiteful, prideful, ignorant, stubborn, selfish, and maybe some others, including unwise. You have to hand it to him he did the thing that you might of done, if you were in his shoes (figure of speech)(if you were him).