You can contaminate all three vials if you use the same needle to draw from each of them. I’d be very cautious about that, as contamination can lead to serious infections, including sepsis, which is definitely not something you want to deal with.
Personally, I would use a separate sterile needle for each vial and for the injection, even if it costs a little more. Health and safety should come first, especially when using research compounds or products from sources where sterility and quality testing may not be fully verified (more important the specific vials and kits u use are not tested seperately)