It takes a while, a good overlong while, for the Thai thriller “Ghost Lab” to get going. But man, once it’s on its feet, saddle up for a fun ride. Hair raising moments, touches of pathos, gonzo violence, decent effects and the occasional laugh.

Director and co-writer Paween Purijitpanya flirts with “Flatliners” and “Ghost” in this Around the World with Netflix tale of two surgical residents at a Thai hospital who resolve to prove “that ghosts are real.”

Wee and Gla have been close friends since med school. Wee ((Thanapob Leeratanakajorn) is the sad, nerdy and serious one, doting over his dying, hospitalized mother. Gla (Paris Intarakomalyas) is the handsome practical joker, always pranking Wee with fake “ghost” frights.”

But Gla has a secret. He’s been “researching” ghosts ever since childhood, when he was sure he saw his dad shortly after his father’s death. He’s traveled to Asia’s great haunts, even that cursed “Suicide Forest” in Japan. He’s interviewed scores of people with ghost sighting stories.

Although he hasn’t seen one since the night he saw his father, Gla is sure they can “prove ghosts are real.” Wee, facing his mother’s impending death, signs on and the two of them — young men of science — start working the problem.

First question, “How can ghosts be real?” Physics isn’t much help. Are ghosts “photons” or “energy?”

But as they question how ghosts manifest themselves, why they would and to whom, they figure they can “group” ghosts and perhaps make some progress.

Wouldn’t you know it, right after swapping jokes with nurses about a corpse that came in, burnt to a crisp, Wee and Gla see the victim (digital, creaky stop-motion) manifest itself in the dark of the break room.

There’s CCTV video from all around the hospital showing filing cabinets opening, chairs sliding across the floor and wheelchairs navigating empty hallways. There’s lots of death in hospitals. The ghost-hunting duo figure they’re onto something, especially when they stumble into a “dance of the wheelchairs” in one gloomy corner of the basement.

How to get ghosts to manifest themselves in ways that allow others to see, audiences to be convinced and science to accept a research paper? Their “solutions” to that quandary take up the latter half of the film.

The hair-raising moments come in underlit scenes of empty with objects moving under their own power. The pathos comes from death and loss as these callous “cutters” face the limits of their callousness, and make ridiculous leaps to “prove” their point.

And the laughs burst out of the blasts of profanity at each gobsmacked “Eureka” moment of discovery.

The dialogue is largely corny, and the “Ghost” moments, meant to tug at the heartstrings, are few. As I said, we spend the lumbering first act and part of the second hearing “I think I was born to prove to the world that ghosts exist,” and the like.

But after that patience-testing/bar-lowering first half, I was quite impressed by the second. Sure, it’s a mixed-bag, sentimental and soft even as the story contrives to put the friends at odds, with deadly consequences. But “Ghost Lab” has flashes of style and wit that suggest we’ll be hearing more from this filmmaker, and that it could be fun.

MPA Rating: TV-MA, violence, profanity, suicide

Cast: Thanapob Leeratanakajorn, Paris Intarakomalyas and Nuttanicha Dungwattanawa

Credits: Directed by Paween Purijitpanya script by Paween Purijitpanya, Vasudhorn Piyaromna, Tossaphon Riantong. A Netflix release.

Running time: 1:57