What affects the rush incident rate?
There are mainly 3 factors which seems to take effect on the rush accident rate:
- The summed amount of stats. For example the Reactor: I have one reactor with 3 People inside it, all have around S:3. It has a higher accident rate than a room with just one Person in it with S:10, but the same accident rate as a Person with S:9. This leads me to the conclusion, that the right stat in sum(!) will take effect on the accident rate.
- Beside the correct stat for a room (S:Reactor, P:Water, A:Dinner,...) the L factor takes effect. Just like in the real fallout games too. L will always improve percentage values. In this case I have a room with same needed stats (S:9 for example), one with L:2 one with L:8 (maybe due to more people in it). The room with higher L has a accident rate of 14 as the other room has a accident rate of 19 percent.
- The time! If you rush a room too often in a too short range of time, the accident rate will grow. On rooms with a good stuffing (high stats which are needed + luck) your able to rush 1-3 times before it will get to a "critical" accident rate of 30%. After a few collections it's back to its original accident rate of 10%.
Hopefully this will help you.
I failed a 3 percent rush this morning in my water treatment plant (size 1) with two dwellers. Dweller 1 had 8 (+5) perception and dweller 2 had 9 (+2) perception. In addition dweller 1 had 3 luck and dweller 2 had 9 (+1) luck. I succeeded at rushing at 13 percent right after, and then rushed again at 23 percent and failed. I don't undertand what's going on behind the scenes at all. I also tested the probability of passing at rush at high percentages. I rushed a room with 6 dwellers (not sure of the exact stats) again and again at 80 percent and 90 percent (after it goes up to 90 and you fail, it goes down to 80 immediately). I rushed maybe 50 times and never succeeded one time. The probability of failing seems much higher than passing regardless of percentages.
Failure rate = 40 - 2 * (Average room Luck + Average room Skill) + 10 for each successive rush (up to +50)
Use one maxed dweller in a tripple lvl 3 room and you always complete the first rush.
Average room luck also increases chance to get +200 caps when picking up reasources.
Source: https://docs.google.com/spreadsheets/d/1Nai09D_aM2syl3iPP5hkveDcOUwhsoUDR6s1lwC0e8c/htmlview?pli=1&sle=true#