29: It is interesting that John specifically points out it was a hyssop branch they used to give Jesus the sponge of sour wine to drink. Hyssop was used as a part of the Passover ceremony to paint the blood on the doorposts. (Exodus 12:22) John is telling us in as many ways as possible that Jesus is the fulfillment of the Passover.
34: Blood and water. On the one hand a clear medical sign he was dead, on the other hand a clear symbolical sign that through his death, he became the Source of Life.
35: Very important to realize the genre John is putting his book in through this statement: Testimony. In other words, P says A. We believe A because it is P who says it. If we choose to not believe A, we thereby are automatically accusing P of being not trustworthy, and should only do so if we have good reason to doubt P (yes: P, not A). (Got this from Vanhoozer's great book "First Theology")
41: And here comes the next big key word: garden. John is pointing us to the garden of Eden and saying that the death of Adam was now entirely fulfilled by the death of Christ. But luckily, things don't end here.