The first panel alone tells you what's going to happen. The other three panels aren't even needed.
Though, I suppose one can question Youmu and Reisen's judgment considering Yuyuko a few strips ago.
Would you like some tea? ♪ Reisen-san, you eat way too fast! LOLAh, please don't mind me...Er... ah... yeah... Sorry...Could you take those tea cakes over to Reisen-san?I am certain that there was something atop this plate...I don't really understand how, but I must have eaten them. That must be what happened.