The odds:
-Getting HIV while bottoming is 1/154 (.65%)
-Condom breaking is around 2-3% on the brands trojan and durex based on their yearly analysis
Since the efficacy of Prep is stated to be around 96%. This lowers the chance of getting infected to .0002%. Although recent scientific studies say it may have increased.
The odds of having the condom break while your on prep, and getting infected by HIV is... well you get the picture.
Although things to note is that the population size is quite smaller and not representative of the real world. So take the statistic with a grain of salt