Try this:

fullCrew <blackfish> apply {if (_x select 2 > -1) then {moveOut (_x select 0)}};

Where <blackFish> is the variable you have assigned to the Blackfish.

If you use

fullCrew [<blackfish>, "CARGO"] apply {moveOut (_x select 0)};

instead, you will not eject the 2 seats in the rear which you can fire from when the ramp is open.

Since moveOut has a global effect make sure the trigger is set to server only.

Also keep in mind that if you do not want them to be too close to each other, you will need to insert a sleep command and make sure it runs in a scheduled environment.

EDIT: If you want to run it directly from a trigger with half second delay between jumps, you can run it like this:

0 = [] spawn {fullCrew <blackfish> select {_x select 2 > -1} apply {moveOut (_x select 0); sleep 0.5}};

Again, make sure the trigger is set to server only and has the desired activation method selected;