As the beast had suddenly gotten stronger, Rein asked everyone to be defensive and not to get hurt. Even though they had healing medicines with them, getting hurt in this situation would not be a good idea. After enduring the boosted beast's attacks for five minutes or so, the beast suddenly let out a very loud roar and immediately died afterwards.
So it looked like whatever happened with the beast, it did make it stronger but at the cost of their life force. So if someone was capable of enduring the beasts attacks for some time, then the beast would automatically die without anyone else doing anything.
This was a very good news for Divine Scale Pavillion's team. They were already the strongest when it came to defense so the current situation was favourable to them. But the disciples would also be in a lot of danger as, if any of the attacks were able to break through the defensive skill of the disciples, they would most likely die immediately.