The "mercy" of Antichrist maybe.
To play Devil's advocate, the man did aggressively approach the altar and head straight for the "priest." So, it's not like he was completely innocent. I would probably move to help subdue someone if they headed straight for Father in my parish. That said, this "priest" was obviously in the wrong here.
Attached is a Chiesa Viva pamphlet I came across the other night talking about an icon of "mercy" in the ʝʊdɛօ-Catholic Anti-church, as I see it mildly relevant to this "church of mercy."