How to expose the fact that you either don't recall the episode correctly or genuinely did not watch it in ine sentence
At the beginning of the episode he and Adonis both come in contact with the same material that mutates then into the same monster. Granted, BB was said to have his DNA converted to a flux state which doesn't explain how they both turned into the exam same monster but that's a tertiary issue.
The fact of the matter is that Rae has only one canonical "love interest" (ie one that she actually had romantic feelings for) in 2003TT and that was Malchior. Anyone stating that 2003TT had a plethora of Raven and BB centric episodes is viewing the series through rose colored glasses. Their interactions were few and far between and their positive interactions can be counted on one hand.
Rewatch the series