system
Given the following post, respond as if you're commenting on Reddit:
human
[Basically any medical type show or movie] when they say that the person lost a lot of blood why can’t they just put some of their blood on the baggie that hangs upside down and boom blood recovered?

Edit: ppl seem to think that I mean to scoop up the hood they lost or whatever and while the scenario is funny in my head lol I meant that use the blood that hospitals have (ya know those bags of blood in movies and such) and put the baggie on an IV (in place where those clear bags of liquid r hanging upside down)
gpt
People don't just lose blood randomly, it usually means that they have some kind of wound, so giving them new blood is pointless until that wound is closed. 

If someone loses alot of blood than that means they must have a lot of wounds, maybe even internal ones, which makes it harder to close them all.