(Third person POV)
Having been left alone in the laboratory, Desmond decided not to waste time and place the bowstring left by Sasha on his new and improved weapon; When he took the rope out of the case in which it was delivered, Desmond could see that it seemed to be made of some material similar to the cartilage or tendon of a beast and associating it with what Sasha said, he assumed that it must have been part of the joints that allowed the Dark-edged creeper tiger executes those ridiculous movements with its tail.
Having both bows and strings in hand, Desmond noticed that due to the subtle changes in structure that the bow had undergone, it no longer had a suitable part to place the bowstring; for the now dark and solidified flowers at both ends of it were in the way of this work.