Although it's going to be back for a second season in 2018, Westworld's season finale, 'The Bicameral Mind', wrapped up many key questions, including the nature of the maze, the Man in Black's quest and Ford's new narrative. The future of the park looks to be bathed in blood after Dolores achieved consciousness and began a massacre of the Delos board, but fans can rest easy that most of their big theories were addressed.
One thread left hanging, however, was the fates of Westworld staff Elsie (Shannon Woodward) and Stubbs (Luke Hemsworth). Both had been members of the park team that questioned some of the more mysterious goings-on and sought answers. Both were seemingly killed when they got close. The stranger case was Elsie -- although we eventually learned Bernard attacked her, we never found out what he did with her.
Some details surrounding her disappearance have come about thanks to secret pages on DelosIncorporated.com, an official in-universe website. Savvy Reddit users managed to crack a line of code from the end of a hidden video (which may also confirm when the show is set) and found the URLs for two new pages on the site. The first is a quick video of Elsie's tracker's last known location, the same blip that sent Stubbs looking for her and (presumably) to his doom, while the second is a short audio file of the programmer saying "hello". Both are presented entirely devoid of context, but could definitely point towards Elsie somehow surviving her assault by Bernard.
The way the show handled the disappearance of these characters was indeed odd. Elsie's strangling was shown in brief flashbacks from the highly unreliable narrator Bernard, while little is known about the "Ghost Nation" who attacked Stubbs. That they're the ones being referenced by HBO following the finale seems to be a subtle way of suggesting that wasn't accidental and more is to come from these two employees.
How exactly is incredibly unclear thanks to the vagueness of the evidence. A fair guess would be that Ford wanted them out of the way so they didn't interfere with his plans but as innocents felt they should have a chance to survive the new narrative. This would put them in prime position to be desperate survivors against the backdrop of the host uprising in season 2 -- rather fitting given Elsie's comments early on in the season regarding Stubbs' seeming desire to be part of the game. On the flipside, they could have been secret hosts all along and taken by Ford to be worked into the narrative itself.
Whatever the case, the core survival mystery could be solved a little bit earlier than the show's return; a cast list will give us an idea of if the characters are alive or not.
Westworld will continue with season 2 on HBO in 2018.