Shalom,

It seems like some words were cut out from this insight. I found the original, raw file, which says as follows:

(c) Tosfos asks questions on these first two answers, and therefore entertains that the question is indeed according to Beis Shamai. The question of the Beraisa is how we know that one sprinkling is enough. It would seem that we should derive from Chatas that two sprinklings are required!

A more comprehensive text would be as follows:

(c) Tosfos has difficulties with these two approaches, and therefore he suggests that the Beraisa indeed follows the view of Beis Shamai, because, according to Beis Hillel, we do not need a verse to teach that one Zerikah of Dam suffices for Korbanos other than a Chatas. There is a general rule in Kodashim that when a verse does not state a command twice, that act is not Me'akev. Therefore, since the Torah does not repeat for the other Korbanos that the Dam must be sprinkled as "two that are four," that full pattern is not Me'akev; nonetheless, at least one Zerikah is certainly required, because we do not find Kapparah without any Zerikas ha'Dam at all. The Beraisa's question, "How do we know that one sprinkling is enough -- it would seem we should derive from Chatas that two sprinklings are required," arises only according to Beis Shamai, who maintains that for a Chatas all the Zerikos are Me'akev and we should learn from Chatas once we have a way to do so, that the full pattern is Me'akev.

Kol Tuv,

Aharon Steiner