Le bretteur wrote:
We understood that the [Field Operative] player will always roll his 5 dice on beginning of his turn. [Any previous used] sample [action dice] being not locked [up along with any infection dice placed on the Field Operative's card]. Is that right?
The meaning of the phase "set aside" in the role's power, "Whenever you Collect a Sample, put just the Infection die on your Role card, setting aside the spent [collect sample action die]", is the normal setting aside of spent action dice after they are used during a turn (see base game rules, page 3, After Each Action).
Don't confuse "set aside" with "lock up".