Well they have the ability to heal, revive, buff health and likely other buffs. I am not sure about the poison ability, takes away from the healing bit.
They probably don't have the poison ability, but it could actually be a good idea. The operative could have an ability that basically just uses a syringe to inject a target with a neurotoxin, causing a certain effect. One could be similar to tetradetoxin but only slow the target to a certain extent, or another could make the target less accurate, and would only work for a set time such as until death, or a medic cures it.
I on the other hand, thing the medic should have an adrenaline sort of ability, used on a friendly target, that could increase accuracy or fire rate for a set amount of time.