Trouble? I LIke It!

Another interesting thing to note is that as cultivators, they could lose their arms and limbs and still have them reattached magically under a specific dateline, depending on their current cultivation realm. 

If one's arms were born out, they could still get them out. But the time to recuperate and fix one's qi channels would take time to heal. 

So, why not allow them to face such brutalities before rescuing them when they feel that all hope was lost?

Bottom line, no one would be dying on the island. But that didn't mean they wouldn't experience hell!

That said, things wouldn't always remain like this.

After the war, if anyone entered the forbidden forest, that was your bloody business. 

Only those on the actual academy grounds would be kept safe from predator attacks.

If you feel you have all the luck in the world to go against a situation entirely disadvantageous to them, then be his guest!