It is inconceivable to leave someone behind. Once the exit gates are powered, you gain the following effects:

50/75/100% additional Bloodpoints for healing and unhooking other Survivors.

30/40/50% bonus action speed when healing and unhooking other Survivors.

When unhooking a Survivor, they gain a 7% movement bonus for 10 seconds.

The auras of all other Survivors are revealed to you.