It's revealed in Episode 6 that
Verna is some kind of entity that makes deals with people to make them rich and powerful in exchange for likely similar deals that she made with the Ushers. She's shown with Zuckerberg, the Rockefellers, modern politicians, and even the founder of Monsanto in 1901.
So given that it's likely that she made deals with all these people's parents as well and has been tormenting them alongside the Ushers. The people at the party were all part of the deal.
It should also be noted that Verna never does anything herself to lead to these deaths. She psychic drives the Ushers to make decisions that end up costing their lives, and sometimes people get hurt along the way. It is not Verna who kills these people. It is the Ushers and their ego/obsessions.
For example, in episode 5,
Verna psychic drives Victoria to have a fight Dr. Ruiz. Victoria, by her own decisions, kills Victoria which is the jumping off point that ultimately leads to her own death.
So in the case of Perry, Verna did not kill those people at the party herself. All she did was appear on the rooftop of the factory which allowed Perry to see the water towers that held the acid. Perry, by his own decision, decided to hook up the water towers to the sprinkler system because he absolutely needed this party to go his way. So it was Perry who ultimately lead to the deaths of all those people.
Is there any hidden meaning
From a story telling point of view, this episode is a modern adaptation of the short story The Masque of the Red Death by Edgar Allen Poe. In this story, a rich prince named Prince Prospero invites 1,000 noble guests to a luxurious party to escape a plague knows as the Red Death which has been ravaging the countryside. He barricades the entrances such that nobody can get in or out. When the clock strikes midnight, a mysterious masked figure in a red robe appears. Prince Propsero pursues this figure only to suddenly die when he finally confronts it. The other party goers rip off the mask and robe only to reveal that there is nobody underneath, and it was in fact the Red Death. They all flee in terror but are unable to leave. They all succumb to the Red Death.