How did Firestar Graystripe and Ravenpaw helped Mistyfoot Feathertail and Stormfur to escape from RiverClan when Tigerstar kept them as prisoners?

ravenpaw pertended to the shadowclan cat that he was a riverclan cat,and that tigerstar wanted him,so when the shoadowclan guard left to get tigerstar,greystripe pavenpaw and firestar((i think of was it fireheart at that time?if or get lolz))go into the prision type hingy and rescue them :D