Escape the Reactor
Small platforms will rise out of the water below. The fireteam must make their way across the chasm by jumping on the platforms. Only one Guardian may stand on a platform at a time; if more than one Guardian stands on the same platform, all of the platforms will fall and the team will need to start over.
Defeat the Loyalists
Several waves of enemies appear. After defeating them all, Calus will open a door in the middle and tell the fireteam to continue further.
There will be cover on a long path in a huge room. Periodically a ringing and then a flash will occur; if a Guardian is not behind on of these barriers, they will be killed. Once past, the fireteam will have to run down a long barrel of a gun and will get shot into a gun. Afterwards the fireteam will have to descend through the debris of Nessus and go through 6 rings floating in the air. If the fireteam activates all 6 rings, they will be rewarded with a loot chest.