FAQ for
Event Horizon (1997) More at IMDbPro »

Weir stops the crew from leaving the ship by putting a bomb on the Lewis & Clark. Weir then activates the Dimensional Gateway to send the ship back to hell. Miller gets the plan of blowing up the central corridor of the Event Horizon to use the Forward Decks as a lifeboat, but after activating all the bombs, Weir traps Miller in the Gateway room, but Miller detonates the bomb anyways. Sacrificing himself to save Starck, Cooper and what was left of Justin.

The gateway opens, taking Miller and Weir to Hell, while Starck, Cooper and Justin are supposedly rescued.

Weir built the dimensional gateway and the rest of the ship, it was his baby essentially. He was more devoted to it, than he was to is own wife. The ship disappeared, then 7 years later it re-appeared. Once on the ship, it started showing him visions of his wife, probably promising him they could be together. There are a few shots of the gateway flashing into his mind, probably voices in his head so to speak, seducing him. The ship needed a Captain, someone to activate the Gateway, who better than it's creator?

When Justin investigates the Gateway, it opens by itself, pulling him into it. However at the end of the film, Weir needed to activate it to send the ship to hell.

It's possible that the ship can open a portal, a doorway into the other dimension. But someone needs to activate the ship's drive in order to send the entire ship to hell. Because if the ship could send itself it probably would have done that as soon as everyone was on board.

As described in the film, the ship went to hell. However, this will depend on one's interpretation of hell. The film depicts hell as a scientific possibility and not a spiritual myth. This hell is another dimension from our world where it seems to be based in a sadomasochistic torture realm (much like Clive Barker's Hellraiser)

The Event Horizon was originally designed to create an artificial dimension that would in a sense, punch a hole in the universe that would allow the ship to pass through from one point instantaniously to the next. But it wound up opening a gate way to an ACTUAL dimension, that unfortunately was Hell. The reasons for this are never specified, but given Weir's confusion and hesitation to tell the truth to the other crewmembers, the fault lies with him. He likely screwed up the math at some point.

They killed each other through sadomasochistic orgies in which they mutilated each other in a sexual fashion.

He sacrfices himself to save the rest of his Crew, he is sent through the dimensional gateway along with Weir. Now, if there's any spiritual factors to the film's version of hell, he would be saved from the realm and ascend to heaven for his self-sacrifice. If hell is a physical realm, then he would die a horrific death, but once he died he would no longer be trapped within the realm. Or if you want to combine the two, he would die a horrific death within the realm, but once he died his spirit would ascend to heaven.