Learn To Code 2 - Up and Down - code issue

Hi, I'm a beginner on Playgrounds and I don't understand what is wrong with line 04.

I expected to choose which character will perform the maze with right hand strategy but it looks like I failed.

Can someone please explain me where is the mistake?

thanks

while gemCounter < 7 {
    if character.isOnGem {
        gemGem()
    }else if character.!isBlockedRight {
        character.turnRight()
        character.moveForward()
    }else {
        character.moveForward()
    }
}