>>1362138But the guy hated anime, that's why he torched the building.
From what we have, he was sending them death threats and announcing his plans on 2ch for a long while, while using his supreme trainspotting skills to watch the building and do research on its floor plans and timetable, culminating in him walking in on the day the security was down due to a meeting, locking the sole emergency exit and dousing the the main exit with gas, then proceeding to camp it with leftover gas and knives.
