https://www.youtube.com/watch?v=Ejn54A3wAbM
Safe until you cock it. Cock it doesn't look hard I've not done it personally though.
I don't see the problem with manually placing the cartridge in the chamber in a single shot bolt gun. It may be difficult for an adult with big finger to do, but shouldn't be too hard. I manually loaded a single shot target gun in this manner without problems when in college.