Guest Lin, how horrifying! And I imagine very dangerous, as oxygen administered like this can explode if a burning cigarette ignites it.
Addicts don't care because their lives are already forfeit. We often see a pitiable young chap sitting on the pavement in Norwich's main shopping street, The reason he's sitting is he has had a leg amputated. It became gangrenous due to infected veins repeatedly injected with heroin. The reason he's begging is he needs £10 for a fix. I've seen him leap up onto his crutches and hop away to buy it when a kindly-intentioned person has given him money. The reason I know his story is that I heard it from an inmate in Norwich Prison. The poor chap is well-known. I refuse to give him money but I do buy him a packet of sandwiches and a carton of coffee. He never looks very pleased though. Heroin is all he wants.