Since POX vials works as a grenade, it should be able to be stored in vests grenades slots. I dont know if its intended, so correct me if I am wrong. Also after the gas from bombed cities disappear, you can find around 4, sometimes even 5 pox vials on the floor, maybe restricting it to 2 at maximum would be better. Also the pox grenade launcher ammo spawns erywhere, and not only at static toxic zones.