IIRC, if you start to unscrew the bolt shroud with the safety in the fire position you get about 1/4 to 1/2 turn, the striker gets uncocked and you can't unscrew anything anymore, but you can screw everything back into position.
At this point you have a bolt assembly that's outside the rifle but with the striker and shroud rotated such that the bolt is in the same configuration as it would be if it were in the rifle, closed, and uncocked. To fix this all you need to do is rotate the shroud around the bolt so that the striker is cammed back into the position it's in when you lift the bolt handle. Mentally, picture the bolt body as a bottle and the shroud as the cap that you are trying to unscrew. You can do this with your hands or you can put the shroud end in a vise (use leather to protect the metal from the jaws) and rotate the bolt body using the handle for leverage. The vise method takes the same effort as lifting the bolt handle, the "unscrew the cap" method takes reasonably strong hands/arms and a good grunt. Probably a good idea to wear gloves for that one too.
I guess maybe your problem is different, but I learned the hard way why the safety is supposed to be in the middle (vertical) position when you strip the bolt.