new_code.c

// this is the new behaviour. You set a global varaible inside the lineFollower task and then use it inside an arbiter.
// forage variables are show to give an idea of how it works. 

int forage_left, forage_right, follow_left, follow_right;

task arbiter(){
  if( follow_left || follow_right) {
    setMotorSpeed(left, follow_left);
    setMotorSpeed(right, follow_right);
  } else if (forage_left || forage_right) {
    setMotorSpeed(left, forage_left);
    setMotorSpeed(right, forage_right);
  }

}


task lineFollower() { 
    // all of your logic but using 
    follow_left = 30;
    follow_right = 30; 
    
    // when following is done and you want to forage. 
    follow_left = 0;
    follow_right = 0;
}

old_code.c

// This is basic line following behaviour, you set the speeds inside the lineFollower task.

task lineFollower() {
  // all of your logic and when you want to move
  setMotorSpeed(left, 30);
  setMotorSpeed(right, 30);
}