Movies in which Two or More People Are Held in a Confined Space with No Idea Why

A while ago, when I asked for feedback on this blog, my friend Megan's husband said I should review a couple of movies in the same genre together.  I explained that I didn't actually want format feedback, because I'm pretty much doing this blog the way I do it - I wanted more content feedback, since some posts are long and involved and others really have very little info in them.

That said, lately I've been watching a ton of movies where two or more people are held in a confined space and have to figure out a number of things, including why, how to get out, etc.

To help you navigate through this genre, I am listing the ones I've seen, including the basic plotline.  They're all pretty good, although #1 is the best.  If you can think of one I've missed, let me know and I'll include it.

1. Saw, the first one:  This movie is ridiculously good.  It was the first movie of its type, not to mention the first movie in years to bring "horror" movies to a new level.  The third and fifth one are also good, but I wasn't that huge a fan of 2 and 4.  After that I stopped watching but aspire to catch up someday.  The plot, as far as I remember it, are that two men wake up in a large, really gross bathroom-ish place, with instructions about how to escape.  There's a saw, and some other stuff.  Neither knows why he is there.  In the meantime, other people are being killed in torturous ways, each for some judgy reason kind of like in the movie Se7en.
2. House Hunting:  This Marc Singer vehicle involves two families who are looking at real estate.  When approaching one house, they find a disoriented, freaked-out girl running through the woods, so they pick her up.  After that, everything they do leads back to that house.  There's no way out. And they don't understand why they're there.
3. Nine Dead: This Melissa Joan Hart thriller involves nine people who wake up in a dungeon, each handcuffed to his or her own private pipe.  They have to figure out what they all have in common, or else every 10 minutes one of them will be killed.  But even if you're killed they still have to figure out what you have in common with the rest of them, only you're not there to help.
4. Hunger: Five people wake up in a cave-like-well-type place with no food, so their captor can see whether they'll eventually eat each other.  
5. Truth or Die: Five young Brits drive to the country to attend an acquaintance's birthday party, and end up being held hostage and tortured 
6. ATM: Three coworkers are held hostage at a freestanding ATM building by some dude in a parka, despite their efforts to make him go away
7. ???: I saw another movie like this awhile ago, where a bunch of people think they're applying for a job, and it turns out they're being held hostage.  I can't remember the name, let me know if you've seen this.
8. Elevator: Nine people are on their way to an investment group's cocktail party when they get stuck in an elevator.  They have to figure out which one is harboring major resentment and an even bigger dangerous secret!
9. Vile: Seven people find themselves in a house with weird contraptions on the back of their necks.  They have 24 hours to torture each other to get enough neurochemicals to drain into the contraptions before they all die.
10. Die: Six people are forced to determine each other's fate with the roll of a die.  Lots of backstory and consequences.  
11. Unknown: watching it tonight