private IEnumerable<(int XPosition, int YPosition)> GetFreeLocations()
{
    for (var index = 0; index < ClaimedCellsBitmap.Length; index++)
        if (!ClaimedCellsBitmap[index])
            yield return GetLocationFromIndex(index);
}

public (int XPosition, int YPosition) GetRandomFreeLocation()
{
    return GetFreeLocations().ElementAt(Random.Instance.Next(GetFreeLocations().Count()));
}