Why is the Ancient One so resistant to the UV Light? The vampires burst into flames within seconds, as does Joey, but the Ancient One, while he gets slowed and a bit smoky, doesn't burst into flames? One YouTuber analyzing the plot gives the answer: The Ancient One is covered in 4000 years worth of dirt and grime, and, being a reanimated human has no sweat or perspiration in order to clean himself, and so the effect on his skin is weakened: Whereas vampires, who spent their time in cocoons, are clean.
Randolph claims that he caught a vampirized Lady Bradshaw draining Van Hyuten's blood. Eagle-eyed viewers can take a quick look at Lady Bradshaw's corpse and discover that she lacks the characteristic fangs of the vampires, which, as Joey and/or Rachel show us, take hours at most to set in, so that can't possibly be true: In fact, her normal teeth are in place, so the fangs couldn't have fallen out after death. Van Hyuten's corpse has the bite marks which shows he was drained of blood, so Randolph's only lie is that Lady Bradshaw was the culprit. Who could it have been? The only vampire was his wife, Mary. It is likely Randolph found Mary draining Van Hyuten. He then overpowered her after she feasted and brought her back to her cell, securing her, but not having the heart to kill his beloved. He probably murdered Lady Bradshaw later, as Randolph knew Lady Bradshaw knew about the vampires and allowed his wife to be killed by them. He then lied about Lady Bradshaw being the culprit because he didn't want his beloved to be memorialized as a murderer.
However, Mary is infected in on 28th Decembernote 28th December. God, forgive us. For days, we have studied this dead, silent realm and it's entombed abominations. Now, the horrors have come for my own dear Mary. Crow found her unconscious in the Star Chamber, her notes scattered around her. and her fangs don't grow out until she's died a "natural" death at the hands of the parasite. note 31 December. Mary is dead. I sat with her in her final moments, telling her how sorry I was. Sorry for accepting Bradshaw's offer. For ever coming to this hell-forsaken place. For placing my vanity above our love. When Mary spoke about "the end of everything", I knew she sensed death coming. With her last words, she made me swear to bury this place. [...] 9PM. Something unholy has happened. As I sat with my wife, I noticed something in her hand; Lady Bradshaw's brooch. She must have pulled it from her shirt when she grabbed at her. Turning it over, I noticed that it looked like one of the creatures we exhumed from the cocoons. Were these the demons Mary had spoken about? Had Bradshaw known all along what we'd find down here? Then, Mary's corpse moved. It was not my wife - it was something inhuman! It leapt at me, and only the bars of the cell spared me from its fury. so Bradshaw may have been infected but didn't die a normal death so the fangs never grew out as Randolph killed the parasite when he finished her off; he may have actually been telling the truth.
Why is the infected Joey's movements so clumsy and uncoordinated when attacking Jason and Nick at the chasm's edge in the cavern? Because Joey had eyesight-problems needing glasses to compensate for and the duo came across those, discarded and forgotten, earlier on in one of the tunnels. Meaning that the parasite within Joey is left to deal with its host's bad eyesight and its movements hampered as a result from misjudging the distance between it and its prey.
