The way I picture it, is that there are Wookies and Clones w/ Yoda fighting against battle droids. The droids all shut down or are all destroyed or whatever, and then the clones go through their little switch and the Wookies w/Yoda fight back, Wookies ripping arms out of the sockets of clones and whatnot, and eventually they are overwhelmed and Chewbacca is the one that personally helps Yoda.