“Find the Echo Chamber, the location where the Restorative Mind is constructing a time bridge.”
“Enter the Echo Chamber” is an objective in the Strike The Echo Chamber in Destiny: The Taken King
With the final barrier down, it is time to start making your way toward the Echo Chamber itself. The Runner can easily slip inside the next area because the entrance is just behind them. The rest of the fireteam can likely run in because of the Taken Portal. It will soak some hits from the Hydra that guards the entrance to the area. The area effected by Shadow Touched is small enough that you can easily walk through it well before the Hydra destroys the portal. Head over to the right and follow the hallway forward. This will lead you directly to your destination.