I really enjoyed this short episode.
We're 4 seasons in and we still don't know much about the reason ghosts are ghosts and why Alison can see them, ie the world building of the scenario, but we finally get another person who can see them, and a good back story on why with another head injury tying into Kylie's history.
Kylie delivers on the acting and the other characters bring their game too.
Things could have got interesting with this arc but the close it down quickly and believably at the end of the episode, keeping the mystery going and saving the show the cost of Kylie on the budget. An enjoyable and fun 7 mins.