Putting the most favorable, "benefit of the doubt" cast on it possible, it may have simply been that Mecca was in the opposite direction of the crucifix, and the Muslims were just praying as they would under any other circuмstances, viz. facing Mecca.
The crucifix could have been either moved, or if that were not possible, had a shroud put over it while the Muslims were having their prayer.
Note well that I am not suggesting it was acceptable to host the religious observance of another sect, least of all a non-Christian one. (Nor am I suggesting that moving or covering the crucifix would be a good thing, instead of just a "lesser evil".) I am just wondering if the sacrilege --- sticking up one's dupa to Almighty God --- was entirely inadvertent and unintentional, and, as I said, prompted only by the way Muslims pray.