Entirely possible I did the math wrong. It's been a long time since I took statistics.
(1 x .95 x.9 ... x .1 x .05) was my guess which comes out to 2 millionths or so.
Oh, I meant that the final step is literally impossible, you can't roll a 21 on a d20!
Ohhhhh... I misread it. For some reason I thought that if you rolled a perfect 20 on the last step you were free. My bad.
Actually, no, your bad. This is a game breaking bug and I insist you fix it immediately! Lol
I suspect it might be a combination of both of us on this one! Not sure if my writing was the most clear on the roll needed for each step.