I wanted to put it out there that if the mystery child, Xrii, is Mrs. Akai and the sister of Elena Miyano it is possible that Elena did complete the drug before disappearing, but left the working sample with her sister instead of allow the BO to know about it or have it. Mrs Akai then took the drug to escape someone later.
I have no proof for this, but I figured it was an interesting idea to explain why anyone else would be shrinking.