I was softlocked by not being able to find menderbot on my first playthrough, here's the process of stuff that happened which probably caused this:

1. Talked to menderbot about finding keycard
   
2. Went to find keycard
   
3. Found it; read a note written to menderbot
   
4. Mineshaft (presumably) collapsed; I found the memories around this point.
   
5. Found photo of menderbot and friend
   
6. Gave photo to menderbot, menderbot ran off
   
7. Couldn't find them (because of aforementioned cave-in)
   
8. Gave up. Went to rowbot, was told I need to find menderbot

...you can see what went wrong from here.
First-time player so i'm trying to figure out how to complete the game. That's my next goal!