Sorry to hear. That can be really disheartening to keep going in the hobby.
I'm not all too familiar with co2 set ups, but this sort of co2 dump is only possible with in-tank diffusers right. Besides a "end of tank" dump. Something like a external reactor or inline (out of tank) atomizer could come off and dump into the tank. But I guess it would dump into the house.
What if a full 20 lb tank dumped into a average size room with no ventilation, is that very dangerous or deadly to humans? If so, what size tank could fully dump and still cause no harm to humans (5lb. 10lb,etc)?