Here is another photo of a typical IV bag:
The "port" on the bottom right (yellowish color) is where you would insert liquid medications via syringe and needle, by placing the needle through that port and injecting the contents of the syringe carefully into the bag. The area on the bottom left, sticking out, is where you would connect the tubing for the contents of the bag to be administered to the patient.
From this, you can see there is really no way to fit an actual bottle or vial into an IV bag. So, I will just sit here scratching my head wishing I had photos and way to question Alvarez on what in the world he saw or thinks he saw. I still do not believe Murray used a propofol drip on Michael and the only IV bag found at the house was drug-free, with only a fraction of the saline remaining.