Left employer for 3 months then returned - how to explain on resume?

Here's my employment history that I need to figure out how to illustrate without raising red flags:

Company A from March 2006 to July 2011.
Company B July 2011-October 2011.
Company A October 2011-present.

In October, Company A called ME (it was not the other way around; I was doing quite well at Company B) and asked what it would take to bring me back. I was able to negotiate a much higher salary and many other perks, so I left Company B and returned to Company A.

Big mistake, as now Company A is on the brink of bankruptcy, mass layoffs, etc., and I'm looking at going down with the ship if I don't get out now.

I could probably go back to Company B if I asked them, but my pride won't let me do that just yet.

How can I arrange my resume to reflect both the fact that I left and returned to Company A in a matter of months, and also that Company B didn't fire me or something? Should I leave off Company B completely? Or is there a standard way to explain that you left of your own volition on good terms?