Then, with the magazine off the camera, release and wind the camera.
Be careful that you do not touch the shutter at all!
Then push the tab in (still being careful not to touch the shutter curtains at all!), and let it go again.
That should make the shutter fire the first curtain, leaving it with an open shutter with the curtains out of sight and harm's way.
If it (pushing the tab in and releasing it again on a wound camera with the shutter closed) doesn't, there's something wrong with the mechanism.
I think i have mentioned that you should be careful not to touch the shutter curtains at any time, but if not: be, and don't!