Sorry, I just don't understand what you are saying. B and the minic both arrive at the positions shown in my graphic at the same time. I don't know how else to arrive there other than this. Perhaps I could start over and find a different way but I really have no idea how to proceed.
I did find that after I killed the roaches from the NW queen (NE and SE are alive) I can move to the center of the room and down to the entrance hall where I then can kill the roaches from the NW, NE, and SE in the next cycle. Then I can get to the SW queen (minic) opens the door and kill it. But then I can't drop all the trapdoors in the SW quardant.
Any suggestions ... anyone ?