Did they ever come to conclusion who really killed Hye Na (security guy, Mr. Jo)? I completely missed it if they…
At the end of ep 20 when they were showing the pictures they showed the SKY Castle guard inside that boiler room in a red shirt so it was him who pushed her off
For those who may be confused about some matters (e.g how can Da Il pass through walls, doors at certain time and why he can touch the hearing aid), the writer answered some questions through an interview: https://twitter.com/dramony_/status/1042663357315051521
https://www.youtube.com/watch?v=R31jR0j8eio
https://www.youtube.com/watch?v=6H0889B_yvA
https://twitter.com/dramony_/status/1042663357315051521