I know two guys who failed the base check with ryanair first time around, the first guy was put back in the sim at ryanairs expense and then passed the base check second time around. The other guy was also put back in the sim but failed it again a second time - so ryanair put him back in the sim again at their own expense and he passed on his 3rd attempt.
Ryanair dont drop people out of the blue if they have a couple of bad sim sessions thats ridiculous - if someone gets dropped from a tr course or line training/a base check you can be sure they were given every opportunity to succeed.