End too soon. Still better than ending it too late. Also harem ending not like you points at Quintuplet (at least made the end route for every member you coward, look at Bokuben!!)
So, basically, he(or his doppelganger) is deploying the fake bomb to made the park empty, so his sick friend can enjoy the park without any disturbance?
Hopefully the kuudere ara ara maid+secretary onee-san is part of harem. I don't actually care with most other waifu potential, we got a princess onee-san yes, but she's a tsundere, A tsundere can go to hell for all I care.