In the base game the symbols on the Pawns are for flavor, however with these rules each expedition member gets special skills.
LEADER
This pawn can perform an ambush with any card .
NAVIGATOR
You can move or ambush over cracks with a diagonal step .
MEDIC
When your Pawns is ambushed by another player you can bring it to any unoccupied adjacent (in any direction) square to your medic, instead of placing it to your ship. Note: You cannot place the Pawns to North Pole like this.
CARRIER
When your carrier is on the game board you can fill your hand to three cards at the very start of your turn.