- You can get padlocks & even handcuffs with timers on them, some of them are pretty heavy duty, if you don't want to make a trip to the hardware store you can order delivery online.
Combined with a strong cellar door (or a heavy duty steel security door if you must) & there really shouldn't be a problem. Just be sure you put all the tools out of the room before locking yourself in.
None of that stuff is particularly expensive & is all pretty easy to get hold of.
- The other really obvious precaution is to have really big pig-out the day before the night of the full moon, when I say 'big' I mean unreasonably humongous, that's stomach stretching "I'm in no condition to do anything but lie here & be very still in case I hurt myself" huge.
You've said they're psychologically like ordinary wolves during this time & wolves don't hunt when they're stuffed.
- Drugs, off the shelf sleeping pills & whatever else they can get hold of so they sleep through the full moon, a helpful doctor friend (or relative) might be good but so much of this can just be bought online & delivered by post that it really isn't isn't necessary.
A practical knowledge of wild herbs can also stand in for this.
- And finally something topical, "social distancing", go camping.
Make sure you're over a day's journey on foot from the nearest people before the full moon & that you've no other means of transport to hand.
Of course you can combine all four of these with a good solid concrete bunker somewhere in the wilderness miles from anywhere.