i dont understand why sometimes this code works and sometimes i get an infinite loop

    public List<List<int>> roomMatrix = new List<List<int>>
    {
        new List<int> {-1, -1, -1},
        new List<int> {-1, -1, -1},
        new List<int> {-1, -1, -1}
    };

    public List<List<bool>> roomsVisited = new List<List<bool>>
    {
        new List<bool> {false, false, false},
        new List<bool> {false, false, false},
        new List<bool> {false, false, false}
    };

    public List<List<bool>> roomsValid = new List<List<bool>>
    {
        new List<bool> {false, false, false},
        new List<bool> {false, false, false},
        new List<bool> {false, false, false}
    };

    // Start is called before the first frame update