Make no mistake: The dropper bottles that e-juice come in are not constructed to anywhere near the same standard as that of the ones which contain injectable meds. If you want 5 ml out of a 15 ml bottle, for heaven's sake take the dropper tip off of the e-juice bottle and suck it up with your syringe that way. NEVER feed the needle into the dropper tip of the bottle and inject 5 ml of air into it like you've seen the nurse do. 5 ml of air under pressure can carry e-juice a long way... in all directions. 
LFMF

LFMF