Into every game, a couple scenes that not everyone’s enjoying seem to fall. (Heck, even the enjoyment varies. Some people have characters who are into it but are dead bored themselves, or are enjoying the scene but the character has no use for it.) It’s reasonable not to be having fun. We aren’t a tabletopping hive-mind; there are plenty of different approaches and playstyles, not to mention plenty of different characters and personalities through which they’re filtered. And there are, technically, options. Sure, sometimes the scene is something that you can’t reasonably just exit—this is one of the reasons why I’m irritated by a disproportionate emphasis on combat—and sometimes, it’s something that you can’t do something about, but usually, there are options. And, of course, there’s asking if it’s possible to hurry things up, particularly if it looks like other people want to be doing something else, or are keeping the scene going for reasons that aren’t necessarily ‘because this sort of thing is fun’.
If you want the scene to be over, though, there are two major things that really aren’t going to do much but make things worse. (Note that this applies specifically to face to face games; due to some of the differences between speech and reading, there are a lot of things you can get away with via text that don’t work as well in person.)
The first is to start planning for the next scene in the middle of the current one. There are circumstances in which this works. If you’re not in the scene, and you’re planning with someone else who’s not in the scene, awesome. Power to you. You’re keeping two otherwise bored people busy and ensuring that the next scene will be moved along rather than being stalled with more dithering and last-minute decisions. On the other hand, if you’re trying to plan with people who are busy trying to handle an interaction heavy in mental processing, then best case scenario is that they’re going to ask you to please stop distracting them, and the worst is that you’re going to distract them, make the scene take even longer, and irritate them in the process.
The second is to go off and do something else in character—and expect it to be played out in detail. Wandering off is a perfectly valid means of getting out of a scene and limiting one’s interaction with what’s going on, and yes, it’s reasonable to find something that the character who just wandered off can go do. On the other hand, the more attention the GM has to give to the wandering off, the less attention can be spent on attempting to bring the scene to its expected conclusion. If the GM isn’t a particularly good multitasker—or if the GM is but is having to manage too many splits in the party—this isn’t going to end well.
All in all, it’s much better to either find an IC way to hurry things along, or to make an OOC request for things to be smoothed out a little. If you’re not having fun, there’s no guarantee that everyone else is—and if someone else isn’t having fun but hasn’t gotten what they need from the scene, stretching it out is not going to help.