The shakeup at RIM continued this week with the departure of two more executives following a poor Q4 earnings call. Reuters and Bloomberg report that senior vice president Alan Brenner and BlackBerry Messenger VP Alistair Mitchell are leaving the company. The exit of both executives is only the latest in a long line since Thorsten Heins took over as CEO for Jim Balsillie and Mike Lazaridis in January. Balsillie retired from the company just over a week ago, and two other batches of senior executives have already left. It's certainly hard times up in Waterloo, and while there have been rumors of a RIM buyout (and one crazy offer), CEO Heins said during the earnings call last week that RIM is currently open to joint ventures, licensing, and partnerships.