removing a door.. troubles..

[FRpilot]

i was trying to remove my doors so it'll be easier to work on the inside of my car but it seems like i can't get them out. i unbolted the 4 bolts holding the door hinges but when i opened the door, the door was still attached by the piece that keep the door from opening too wide. i dont know what its called, but i can't get the pin out. the pin has a slit and its flared but i couldn't squeezed the pin smaller to get it out or anything else. how do you remove the pins? the fsm doesn't explain how but shows that the pins can be lifted out.