Cerberus jam manga

Cerberus Jam summary:

From Fallen Syndicate: Seri, a somewhat directionally challenged girl, went to Umeda for a job interview. Finding herself completely lost, she stumbles across a slightly opened door and decides to try her luck. She takes the stairs behind the door, emerging on a peculiar street half an hour later. Unknown to Seri, she has just mistakenly entered a place far more dangerous than she could ever imagine.