What a haunting picture.
But miracles have happened before in situations like this. Where the advancing armies were stopped in their tracks by a cross, crucifix or the Holy Eucharist. Saint Clare is a story about the Holy Eucharist keeping the Muslims out of her country.
It’s faith that brings miracles. And sometimes faith doesn’t kick in until the situation gets pretty blooming desperate.
... I mean yes we disagree on exactly what the Eucharist/communion is, but it’s often been treated rudely by intruders without any seeming repercussions. Why should those times you mentioned have differed in outcome? I say faith. Faith that called upon the promise of God to defend believers. That is the faith which God answers, and a sign of Christian devotion would be one logical place for Him to answer at.