I don't understand this at all. So if you were playing Doom, you might get stuck because someone in some random other game needs to find your key? That sounds awful.
It doesn't work as well with linear or mostly linear games.
And as another reply noted, sometimes you get stuck ("BKed"). Sometimes each person has more than one game in the randomizer, so they have a couple of options to play further. Sometimes people go watch someone else play until they're unblocked again.
The organizer can also kick inactive players out and release their checks. You could play solo with one or multiple games.