There's obviously terrible procedures happening at this clinic, involving contamination, but that one video doesn't seem like the culprit. Notice he removes the needle, then injects medicine into a cannula tube, not flesh. He then re-attaches the needle, draws the second dose, and injects again. That was the problem. The narrator says he then used a brand new syringe for every child, but that initial procedure contaminated the vial. Cannula tubes are primed with saline, that's kind of a long gap for blood to travel to contaminate the vial. Yes he did it wrong, but I get why he thought it would be ok.