It is not about how dangerous the flywheel will be. Even though if it is not done properly, and the flywheel get detached and spins off the axel it can be pretty dangerous.
Looking at BLRS video, it is obvious that 1 motor is enough to shoot the disc over to the goal. But I am concern about the cycle time, or how fast the flywheel can “recover” or pick up speed again. Coz we are looking at continuous, rapid firing of 3 discs. But each time the flywheel shoot off the disc, the flywheel’s momentum will be transferred over to the disc, and hence slowing the flywheel down.
There are actually lots of good resources in the forum regarding flywheels.
You can dig around for NBN and TP seasons.
What i can offer you is my shameless plug on this informal, “definitive” guide/thread on flywheels
Do bear in mind that all these were using cortex equipment and 393 motors (which were much weaker than the current v5 motors). And even though the thread started off as a robot reveal, it eventually led to real good technical discussions ( > 450 posts) on various aspects of flywheel design, etc.
Hope it will help you in your journey of learning about flywheel.