The timestamp on the CCTV says "2021-08-03 10:01:12" so from before the victim entered the area.
"According to security camera footage, on Tuesday (Aug 3) she walked out of the hotel about 11.25am to Ao Yon beach. At 11.48am she walked alone on Ao Yon-Khao Khat Road towards Ao Yon waterfall...." (Victim's timeline)