For 6-1, in the first room, for most speedruns I see people instakill both Maurices with the overcharge pump shotgun. I've tried it out myself but cant seem to find a way to consistently kill them. Does anyone know how exactly you do it?

you have to time it so that the projectiles would reflect back into the maurice, but you have to also make sure that they dont go into the SM

you need to get hit by the first projectiles just before you shoot the overpump so you dont go flying. dont dash because it makes the maurices track you and the projectiles dont get reflected