Yeah, shortwave UV scares the piss out of me to be honest, especially in the way it destroys DNA and basically any other organic compound. I have an F4T5 germicidal lamp sealed inside a test tube that runs off a capacitive dropper ballast; the person who made it for me tells me its safe and I'm sure it is, but I still get major heebie jeebies even running it for a short time.
If the UV can not reach your body and no oxygen supply to form the ozone (or a proper ventilation), there is no reason for it to not be safe...
On the other hand the UV is a problem for just the skin surface (and eyes), so it recovers pretty fast. Of course, unless the damaged skin surface is too large, then it becomes problematic (slow recovery, overload of the immune system leading to higher risk of skin cancer,...)