I'm pretty sure Riley was involved in freeing Skylar: as a reminder, our protagonist was being stalked by a mysterious man until Riley appeared out of nowhere and gave him the beating of his life. She also mentions a kidnapping of a girl in that context, and I also think it was mentioned that the principal was involved somehow. Also, Skylar shows up again at the end of the update.
Theory: The director is allied with those who want to use the time travel machine for their purposes. He knows that Skylar and MC are close or at least she is a good friend of the protagonist's sister (MC was followed in this update without realizing it, who tells us that this hasn't been the case for a while?) so there is a reasonable assumption that with Skylar in their hands they would have an important trump card in their hand to blackmail MC. Regarding the blackmail against Krystal and her mother to get malware on MC's phone, this would not even be improbable. So the director hires someone to kidnap Skylar, this works and Skylar disappears for a while. If we assume that Masked Man has a way to travel into the future, it could mean that Skylar's disappearance would cause problems in the future, so he hires Riley, who is probably an ally of Masked Man, to free Skylar. Probably without being seen by her, since her role is probably to support MC from the shadows.