shotgunning prop/fina?

ok guys i know this is really a stupid question but i need to know. I am going to be starting my prop/fina cycle in 2 weeks. Im going to be drawing both of them from a vial. how do you do this without losing some of the lets say prop into the fina vial. when you already have a cc in the syringe and you put it in the other vial to draw how do you keep whats in your syringe from leaking into the other vial? I know this is dumb but please dont flame me to bad.

i wouldnt worry about it,but if your that anal bro,after you withdraw your prop or tren whichever first draw back a 1/4 cc of air and then fill with the rest and just get the air out before you use.