cosima/natasha.
This person is one of three who who arrived at the time and place designated for a HYDRA meeting. They were under suspect by one of the other two, who is now among the missing. They are known to have abilities in the past which have been used to cause people to disappear, and reappear, at their own choosing. This person is a child, and thus one of the most seemingly trustworthy individuals here, which would make her easily used for this purpose by the scientists. Evidence found with the octopus drawing (which could be considered somewhat childish in nature) included red fibers, which are believed to have come from clothing worn by those in Romeo, where she resides.
I understand that there could be ways to explain a great deal of this, but if she is being utilized by the scientists in this manner, we need to stop that.