All humans love themselves, but at the same time find themselves intolerable. Shortly after receiving the assignment, Akane teaches Kotarou how to use familiars.
The cruelty of natural selection, one of many allusions to Darwinism throughout this route. Explanations in this thread have been pretty good, but there's a big aspect that I haven't seen mentioned though I skimmed some comments so I might have missed it.
Everybody slowly comes to accept the loss of their old world and works together to make the ensure the new world has a sustainable future.
Suzaki tells Kotarou that ten years ago his men had captured the Key, but it managed to escape. She seems to be the coldest and more distant member of the Occult Club, mostly just addressing Kotarou instead of any of the other heroines.
After that, she leaves a questionnaire for Kotarou to fill in, and toys with him using different clues and notes including finding a statue of a certain fried chicken chain until he reaches the club room again.
After a few days Kotarou notices three guardian helicopters converge on Martel HQ, only to be eliminated by airborne familiars before they can reach their destination.