What is it that these monsters are safeguarding? It was something for the adventurers to find out after they explore the area.
The thing to note about the Danger Zone is that since it is named as such, there are likely to be areas designated as Safe Zones as well.
Just like what the name means, they were specific areas in the Danger Zones where the monsters can't get in. They were created to provide some respite to the adventurers seeking to explore or clear these special areas.
The cave where Cynthia and the others were currently, was precisely one such place.
"Let's not dwell on that for now" Alvara leaned against the cave wall, wincing as pain shot through her body. "Our priority is to tend to our injuries and regain our strength. We won't last long if we don't recover ". She spoke with a strained voice.