Besides the point that it was necessary for the crew to survive the upcoming battle, I think their was one more reason behind it. After pondering what will happen to the Guts/Beast dynamic if Caska becomes sane again, I figured that Flora knew Guts would seek the Elf King, and bring this event to pass. The armor itself is forcing a confrontation between Guts and the Beast. One that Guts has to win or die trying (though not dead-dead, if Skulley is any indication).
Simply put, Flora wants Guts to be cured of his Beast problem. Since it seems Skulley died after losing himself in the Berserk's Armor, it would seem that stopped him from berserking, since he always seems collected. My guess is that Flora wants Guts to rise up as the counter to Griffith. In order for Guts to be followed, he has to be able to avoid flipping out and killing everyone around him, and still have a human body.
Simply put, Flora wants Guts to be cured of his Beast problem. Since it seems Skulley died after losing himself in the Berserk's Armor, it would seem that stopped him from berserking, since he always seems collected. My guess is that Flora wants Guts to rise up as the counter to Griffith. In order for Guts to be followed, he has to be able to avoid flipping out and killing everyone around him, and still have a human body.