Aha Ok Thank you, I didn't notice that.

A person on 1st floor called the lift.

new int[]{0}, // 1

How come the last test showed the lift stops on the 1st floor?! there is neither queue nor a request to go for the first floor in the queue list?

   int[][] queues =
    {
        new int[0], // G
        new int[]{0}, // 1
        new int[0], // 2
        new int[0], // 3
        new int[]{2}, // 4
        new int[]{3}, // 5
        new int[0], // 6
    };
    var result = Dinglemouse.TheLift(queues, 5);
    Assert.AreEqual(new[] { 0, 5, 4, 3, 2, 1, 0 }, result);