jammed battery panel

hi my brother owns an inspiron 6400, his water bottle exploded in his bag and got inside the notebook i figure it would be sensible to take out the battery to let it dry, but when i pushed the little thing accross to unlock the panel, it jammed and wont move back obviously i dont want to use too much force to move it back in case i break it has anyone else experienced any similar problems? and any ideas as to how i can take out the battery? thanks