When facing the area Victus is on there should be a ramp made from rubble on the left side.

You should get a cut scene after fighting everything in the pit. If you don't fight stuff, the game glitched, and you have to restart the mission.

Fly around the planet.
You never go in a pit, it's simply a lowered area.
Kill all the enemies and you'll get in conversation with Victus whereupon the entire Mass Effect Universe will merge with the New 52 and you'll discover it wasn't actually a bomb on Tuchanka, it was the Black Power Lantern. Malcom X not included.

This actually happened to me on my first playthrough...
I realized that the harvester was suppose to come back around in the pit but I killed him quickly in one of his other appearances.
Restart the mission and don't let the harvester die before you reach the final pit, he is necessary for in-game cut scenes to take place.

You can kill the harvester before hand because there is more then one there are three in the game. If you dont die and you kill every thing in the pit and your still can move on then save and take out your disc and see if it need to be clearned. If that don't work then try looking every were and then you should run into the cut seen.

After killing everything, your two squadmates should be standing to one side of the area near the rubble where victus is. head for them, or just a little part them, and the cutscene should start automatically.