It seems that the fire and radroach emergencies are getting severer and harder to fight in larger merged room and more upgraded room. It is counter-intuitive.
Upgrading or merging rooms should make such emergency easier to handle. On the contrary, it get harder.
For emergency in empty room, it is generally better not try to extinguish. Dispatching dwellers to the empty room in fire takes much longer time to extinguish than leaving the fire burn out without any intervention. Trying to handle emergency on empty room is counter productive.
The game mechanism of emergency in this game is severely broken and irrational and does not add any fun or worthy challenge or compensation. It needs complete re-design from ground up.
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