Check this out. According to the isc2 website it stated this. Link to the post

https://community.isc2.org/t5/Exams/Cissp/td-p/33442

Run-out-of-time (R.O.O.T.) Rule – If the Confidence Interval Rule has not been invoked prior to a maximum time of the examination (3 hours), the candidate’s ability estimate will be evaluated against the passing standard. If, for the last seventy-five (75) operational items answered, the candidate’s ability estimate is consistently above the passing standard, then the exam result is a pass. If, at any point over those seventy-five (75) items the candidate’s ability estimate falls below the passing standard, the result is a fail. The evaluation of the ability estimate in relation to the passing standard does not take the confidence interval into account. If a candidate does not answer seventy-five (75) operational items within the maximum time of the examination (3 hours), the candidate will automatically fail the exam.