Should i take my sister to the emergency room based off of the following symptoms?

basically... my sister was raped when she was 14 and she is 18 now. but recently she wakes up in the middle of the night screaming and crying... and this isn't just... you know... normal screaming. she is terrified and sweating in the middle of the night... and when we try to comfort her she pushes us away as if we are strangers and she yells "GET OUT!! MONSTERS!!! MONSTERS!!!" and she goes into her closet until she falls asleep again. and she has no recollection of it in the morning. i know this behavior is probably a PTSD symptom.... but it has occurred to me that she also might be hallucinating. so far this has happened every night this week. should i consider taking her to the emergency room the next time it happens? if not is there any other advice?