Supervisor Steel has Specialist Blunt follow the arrows.  They come to what might be a door with a doorbell.  Tallgrass puts on his pressure suit and goes out to ring it.  To his surprise, there's an answer.

rjb

https://oliveronline.ca/2018/10/04/the-plainsrunner-chapter-46-47/
https://greencomet.org/2018/10/04/the-plainsrunner-chapters-46-47/