Taku is not above pranking people either. But I guess it's a good thing he doesn't do it all too often. ;;
Now, this dialogue looks very simple, but I had to think quite a bit how to phrase things. In the beginning and mostly as placeholder text, Taku was just like "Looks like she's dead," but I wasn't very fond of that for various reasons. For one, outright telling an already worried person that someone died, even though it's only a joke, is not only in bad taste, but would scare poor Kei even more. The mirror comment does too, but "the mirror getting to her" is a pretty vague comment and could imply ANYTHING. Taku is pretty tactless at times, but I didn't want to go too far with his dialogue. Of course, it was still a mean prank to pull, since Kei automatically assumed the worst anyway because he's just a worrywart like that...