I'm about half way finished with Then We Came..., and I'm still uncertain as to what Ferris's themes are.
One possibility is that he is examining -- through the lens of officeplace interactions -- the way that people view (and respond to) others' tragedies.
For instance, Janine Gorjanc's nine-year old daughter goes missing, and then is killed; her colleagues alternate between (1) trying to be helpful (putting together a missing photo but becoming overly obsessed with photo-shopping the image to make sure it looks just right) and (2) being completely inappropriate (spying on Janine when she goes to McDonald's and mourns in the kids' play area). Also: the group (the "we" that is the narrator) thinks that supervisor/partner Lynn Mason has breast cancer, but they are not 100% sure (there's some concern this is just an unfounded rumor), and they become more concerned with the status of the rumor than with the status of Lynn's health.
I gather from these episodes that Ferris may be telling us this: most people become uncomfortable when reacting to another's tragedy, particularly if the other is an acquaintance but not a close friend or family. We alternate between fascination with the morbid aspects of tragedy and genuine human compassion for the sufferer. I assume he's saying that this is a natural, shared response (and we shouldn't judge ourselves too harshly for experiencing it?).