To be fair, the bomb already went off at that point. Rosa and Maria trying to escape Rokkenjima is nothing but fiction as they already died at that point.
True, and Umineko does do this quite often. Though I would say that the narration does lie to the readers sometimes-like the whole forget me not being a flower for truth when its really a flower for true and undying love.
But I guess no one here really knows that much about guns so we can’t say for sure.