Complex sentence: Just then, Shuu'ichi Akai appears and informs her that he has crippled Calvados, then he shoots Vermouth, only to find out that she is wearing a bulletproof vest.
Split into simpler sentences: Just then, Shuu'ichi Akai appears and informs her that he has crippled Calvados. He then shoots Vermouth, only to find out that she is wearing a bulletproof vest.