"Entering The Portal"

The group could not know the truth behind the underwater town's mystery and other things, but this gate that looked similar to a portal made all of them think of various conspiracy theories. 

"I really think this should be a portal. There's no way to leave the slum so easily when the whole place has thick barriers and a mist wall. If there is a portal, it's much more believable." 

It was not that the monsters in the slum didn't want to leave the slum but that they could not leave. 

Even if they found this light hole, they might not be able to enter the portal for various reasons. 

So, why would there be a portal here? It should be for outsiders who came to the slum but were not forced to be residents of the slum. 

The beasts and intelligent monsters in the town still had the heart to create an exit for the stranded outsiders because the entrance to the slum was a one-way door except for town residents and patrol guards.