file.rs

    fn move_enemies(&mut self) {
        self.enemies = self.enemies.into_iter().map(|enemy| {
            let between = Range::new(0, 4);
            let mut rng = rand::thread_rng();
            let desired_move: (i8, i8) = match between.ind_sample(&mut rng) {
                0 => (0, -1),
                1 => (0, 1),
                2 => (-1, 0),
                3 => (1, 0),
                _ => (0, 0), // This shouldn't happen.
            };

            let target_entity = self.entity_at_square(0, 0);
            
            match self.entity_at_square(enemy.x + desired_move.0, enemy.y + desired_move.1) {
                Entity::Player => {
                    self.phase = Phase::PlayerDied;
                },
                Entity::Nothing => {
                    enemy.move_(desired_move.0, desired_move.1);
                },
                _ => {} // Treasure or another Enemy
            }
        }).collect();
    }