"Sanctum Templar" suggests they work for the Sanctum as a person who guards a temple - in this case, Orphan's Cradle. I wouldn't be suprised if Rosch does not have direct authority over such people, or alternatively it's possible that the Templars are so fixed on saving the fal'Cie (sort of like a cult-like mentality) that they would be the ones most likely to ignore Rosch's request, sort of like SS soldiers being the insanely-loyal elite of Hitler's regime.