Yeah he was probably hoping that with all the blood around Subaru would wake up soon so they can leave. Either that or he was thinking "meh it's not Fuuma's eye so why should I care?"
Which reminds me. If we're going to get mad at people for not doing anything, what about those other X characters? Satsuki and whoever else. They could shoot their crossbows or something, right? I mean, in addition to Fai's eye, THERE GOES THE WATER SUPPLY. I wouldn't think they'd be too happy with Syaoran right now. (Mind, Kamui was the one who got the whole thing polluted with blood in the first place, so I wouldn't think they'd be happy with HIM either.)
Add them to the list of "people who should be doing something". Along with the list of "people who really need to be showing up" (Subaru, awake!Sakura, real!Syaoran), and the list of "people who are going to be showing up sometime in the near future if the plot continues at this pace" (Seishirou, Ashura-ou).