With the movie film it is normally kept at a constant tension with no slack so there is no slippage. I can't replicate that on a 220 spool, it will either spin on or spin off unless I'm incredibly lucky and cafeful.
Yes, I understand your point. Even in the projection booth with equipment designed for the purpose you still have to be careful but it can be done.
I wouldn't wrap film on a small core. The smaller the diameter, the harder it is to wind it evenly. Standard movie film cores are usually 4 or 5 inches in diameter.
I suppose a piece of PVC pipe would work but, then, you're getting into a lot of monkeying around just for a temporary fix.
What about just carefully letting the film coil up, loosely, by its own natural curl, letting it stand on edge then simply seal it inside a plastic Tupperware container or something similar? If you are careful not to disturb it, you could certainly keep film safe for the short term until you can buy more sleeves.
I think putting two pieces of film into one sleeve would be much riskier.