Of course when one of the players leaves the room, a roleplaying game often stops briefly while the other players chat out of character.

Come to think of it, this happens a lot when nobody has left the room, too. Roleplaying games really are a rather unique mixture of in-character acting and out-of-character socialising that you don't get with most other forms of social interaction.

Transcript

Padmé: R2, you guard the room while I sleep. There have been threats against my life, you know.
R2-D2: Hey, I've been flying just as long as you. I was the one doing the flying.
GM: Droids don't sleep.
Padmé: Right. Drinks. Annie, you want a refill?
Anakin: Please. {Padmé leaves}
Jar Jar: Pete, why are you so upset?
R2-D2: I'm not upset. I'm annoyed.
Jar Jar: What happened?
R2-D2: Look, I don't want to talk about it.
Jar Jar: Okay—
R2-D2: How would you feel if your best friend stabbed you in the back?
Jar Jar: Uh...
R2-D2: I was in charge for once. If they'd just followed my brilliant plan we would have nailed that... darned persistent bad guy.
Jar Jar: Ooooh.
R2-D2: And not only did those idiots completely screw it up, they didn't even try to resurrect me afterwards!
Jar Jar: Ben told me that fantasy game was really fun.
[SFX]: twitch {R2 twitches}