You think he's reacting to the mini-Miji. Actually he's just realised that his kid was delivered in an opticians. Unless those eye-charts have a use in childbirth, but I somehow doubt it.
I could only have two hundred and fifty five characters and so I thought to myself: Why not fill it up to obtain all use out of it as I can? So that is precisely what I did, with no rhyme or reason, the entire sig exists purely to exist for it's own sake.