I'm pretty sure there was an extra 15 minutes written and they ran out of money and instead showed flashback scenes like in an anime trying to do fillers.
The missing 15 min between episodes 3 and 4 contained necessary plot elements that were just ouright skipped. Reminds me of the cyberpunk 2077 release, where the pieces were in place for things to be awesome, but the suits pushed it forward too fast and too cheap and the creative team wasn't ready. Funnily symbolic of the themes in most of the resident evil games...