Thankfully this has been fixed for a good while, as Bain now uses his dialogue from the Lab Rats event heist, which is much more certain and uses a more consistent pattern note Simply wait for Bain to speak again after he requests an ingredient. Originally, the best way around this was either to wait for Bain to say the ingredient again (which 9 times out of 10 he would be very specific) or comparing what you heard to what other players heard, as Bains' lines were not uniform amongst all the players. It doesn't help that Bain can either be confusing with what to put in by fumbling between ingredients or combining names, or he'll say "Fuck me", which is a telltale sign that he's uncertain. Did someone use the wrong ingredient or do anything in the wrong order? The meth lab explodes, setting the entire second floor aflame and incapping anyone caught by surprise.
On Day 2, figuring out the right engine requires remembering intel and checking info on boards around the basement to figure it out.Failure prevents any sort of bonus in Day 2.
Getting caught before gathering it all means the Overkill MC bikers will try to burn it, and since it tends to be in three/four separate rooms, you need to be stealthy or carefully plan an assault. Day 1 requires you to steal intel from the Overkill MC.Additionally, the heist depends on getting the right intel and identifying which of the several machines is the only correct one. Playing with neither of these will screw up the entire heist before it's started. If you refuse to play on single-player, you will need either total cooperation between strangers or friends.