Strategy: After the second sword against Crota is complete, the entire team goes down into the basement of one of the Boomer towers--we like to go right (facing Crota). Make sure to not take the bridge because the boomers will shoot you. Take the ground route. Once the team is in, everyone get to higher ground. The first Ogre will pop in the room. Spam him/her with heavy ammo and grenades. Once that Ogre is down, go to the front door of the room and you'll see the other Ogre making his/her way to the middle area. Spam that Ogre with heavy and grenades. It should take roughly one minute to execute this. Exit the room once Crota moves back to the center, and viola, you're on your last sword to beating Crota.