Ending user sessions in 4.2

[PartialTwitch]

I'm running 4.2 on my Nexus 7, and I love the multi-user support. I noticed after signing in as several different users, though, some of the more intensive apps started slowing down noticeably. Going into Settings > Apps > Running, it says that each User account is using up about 40 MB of RAM. Is there any way to complete shut down the sessions running in the background, or "sign out" of a session?