In the Supernatural episode "Heaven Can't Wait" (S09E06) Crowley seems to have nicked one of Sam's syringes and is seen injecting himself. Since he seems well-confined to the Demon Trap, how did he get it?
Even if he just snatched it from the table while Sam and Kevin were getting the translation (@ approx the 36:30 mark) it seems there wasn't much time (about 3 seconds) to grab it, pull a hypo's-worth of Kevin's blood from the bowl, and hide it. Especially since the bowl was only one hypo's-worth to begin with, and Sam is seen dumping a significant amount of blood out of the bowl (@ approx 39:20) and washing it before he notices (remembers?) the bag of syringes. It certainly looked like a good amount of blood in the syringe (@ approx 39:43). It's also a different syringe. At the table Sam grabs the first syringe on the left (@ approx 25:59) but the missing syringe later is the second from the right. Granted, this could be a continuity error, but maybe not.
I'm guessing he nicked it from the table and somehow filled it with Kevin's blood, but it doesn't seem to fit the facts above. Maybe someone else saw or figured out something I missed.
"Seems like you answered your own question" comments are not that helpful in this instance since the blood itself did not seem to go missing. And what else would he be injecting? I hope this is not too much info (including times even) for the question, I just wanted to show I did my due diligence before asking.