Once the Exit Gates are powered, No One Left Behind activates:

Increases your Unhooking and Healing speed by 30/40/50 percent.
Grants 50/75/100 percent bonus Bloodpoints for actions in the Altruism Category.
Grants the unhooked Survivor a 7 percent Haste Status Effect for 10 seconds.
The Auras of all other Survivors are revealed to you.

After a Generator is completed, you will not leave any Scratch Marks for the next 6/8/10 seconds.

When you or the Obsession are injured, you both see each other's Auras.

After healing the Obsession or being healed by the Obsession, you both gain the Haste Status Effect, moving at an increased speed of 5/6/7 percent until you are no longer within 16 metres of each other.
If you are the Obsession, Blood Pact deactivates.
Lowers the odds of becoming the Killer's initial Obsession by -100 percent.

The Killer can only be obsessed with Survivor at a time.

Unlocks potential in your Aura-reading ability:
Paranoia paired with your horror of failure helps prepare you from repeating the same mistakes.

The Auras of the 3 Generators in closest proximity to one another are revealed to you for 30/45/60 seconds at the start of the Trial, and each time a Generator is completed.
Increases your Repair speed on those Generators by +5 percent while active.
If you are holding a Map, all Generators revealed by Déjà Vu are automatically added to it.