User blog comment:Gourgeist/Shingeki no Kyojin Chapter 66 Review: Wish/@comment-7418318-20150210234336/@comment-5433366-20150211101320

I know, I was just trying to point out that the syringe might resemble making the process of her becoming a Titan "clean", if that makes sense.

I think the syringe is for some kind of reason. Maybe the reason Rod is such a huge Titan is because he ingested it the wrong way. Maybe there's a point in the body where it needs to sit. He probably has a large supply of this special liquid stuff anyway, because the Reiss family has been turning into Titans for generations.