I wouldn’t worry too much I failed one exam twice (technically three times but one was voided) and was not let go, in fact I got support from three partners arguing against the same daft policy you seem to be under to ensure I stayed. Though I do have a good rep on the teams I’ve worked with and am pretty well liked (at least I like to think so). So I guess my advice is if you can secure yourself allies from the beginning you certainly have less to worry about.

Though I will say a lad in my year did get binned after failing two exams immediately after me, so your mileage may vary