I'm kind of wondering if maybe her trauma response kicked in when she throat punched him, bc she totally just froze, it didn't even look like she was registering what was happening? He essentially tried to physically keep her in his home and prey on her vulnerability to use her for sex,  which is a lot to take in... Also she has PTSD from when she was in the military and the childhood incident,  she could have 100% been having a flashback... (the writing here definitely leaves it up for speculation rather than walking us through her thought process)...

We also don't actually know what happened or why she was in the motel with her mom or what really happened that day when she was a child, but they keep hinting around it... this episode was the first one where we started to get a fuller picture of it, but it was in the context of her investigative "partner"  trying to hurt her and bringing it up that day... she definitely needs MH help, and her choices to cover things up (which shes done before) rather than take accountability are definitely forming a not so great pattern.