i definitely have benched dice indoors... and im fine
lol as long as you have soem airflow youlle be fine buddy... for the most part your venting CO2 which normally unless you have a high sublimination rate or are benching really hard and getting it very warm will not be excessive. not to mention the acetone running at -50 to -70 you will not even smell as you will be hedging off almost any chance of evaporation. you prolly wont even smell it unless your very close