Don't worry. They're rubber bullets. Marisa has never killed anyone.
Anyway. That wand is basically a quiz show reference, right? You answer Nareko's riddle correctly, she holds the circle side up. But if you answer incorrectly, it's the cross side that goes up... 🤨 Wait, is it really a cross end? Or is it... like, a cruciform base? And you're supposed to place the thing down somewhere?