Ura Baito: Toubou Kinshi - Vol. 1 Ch. 8 - Personal Delivery ③

[MangaDex]

 

[anasnaufal]

The briefcase is the monster or it's a 'womb' that contains the monster and it gets its nutrients from the sanity of people.

 

[friendly]

Huh, so it was harmless to them till now.... did it begin to become dangerous as it fed, or is it from being close to the meeting point...

 

[LupusVir]

Huh, so it was harmless to them till now.... did it begin to become dangerous as it fed, or is it from being close to the meeting point...

I think it's telling them they are running out of time.