After performing a rushed vault in a Chase, Cut Loose activates for the next 4/5/6 seconds:

Suppresses both the Loud Noise Notification and the sound effects triggered by rushing to vault.
Successfully performing a rushed vault while Cut Loose is active resets the timer.
Cut Loose has a cool-down of 45 seconds.

Whenever another Survivor is hooked, Fast Track gains 1/2/3 Tokens, up to a maximum of 9/18/27 Tokens.

You consume all accumulated Tokens after a Great Skill Check on a Generator.
Each Token grants a stack-able 1 percent Progression bonus in addition to the default Progression bonus for succeeding a Great Skill Check.

Reduces the duration of your Scratch Marks by 3/4/5 seconds.
Your Scratch Marks are spaced inconsistently.

Unlocks potential in your Aura-reading ability:
For the duration of the Killer carrying another Survivor, you see the Aura of every Hook within 56 metres of the pick-up location:

The Auras of regular Hooks are revealed to you in white.
The Auras of Scourge Hooks are revealed to you in yellow.
Unlocks the ability to sabotage Hooks without needing a Toolbox.

Sabotaging a Hook without a Toolbox takes 2.5 seconds.
The Sabotage action has a cool-down of 90/75/60 seconds.