Failing a Skill Check while repairing:

Prevents the Generator Explosion.
Applies the default Regression penalty.
Applies an additional Regression penalty of 5/4/3 percent.
Technician reduces the audible range of your Generator-repairing noises by 8 metres.

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.

Your ferocious tenacity in dire situations allow you to benefit from the following effects:

Increases your Crawling speed by 30/40/50 percent.
Grants the ability to crawl and recover at the same time.
Reduces the volume of Grunts of Pain while in the Dying State by -75 percent.

Unlocks the Self-Care ability, allowing you to self-heal without needing a Med-Kit at 25/30/35 percent of the normal Healing speed.

Survivors you unhook benefit from the following effects:

Extends the duration of their Endurance Status Effect by 6/8/10 seconds.
Extends the duration of their Haste Status Effect by 10 seconds.

You can see the Scratch Marks of other Survivors.
Whenever another Survivor loses a Health State within 32 metres of you, the Killers Aura is revealed to you for 3/4/5 seconds.