At the lioness' movement Fin backed way up. He didn't know how else, in Panda form, to convey his intense desire to avoid a fight. Sure, he had good claws, but they were primarily for climbing things, breaking bamboo and the like. He had zero fighting experience. After a moment he noticed that she had settled and was simply looking at him with a cocked head. That confirmed to him that she was indeed a were.
He moved forward slowly, just in case, until he was only a few feet away. he sat back on his butt with his feet splayed out in front of him and raised a paw in a wave.