I was admiring the amazing art book of Hino Matsuri, (lol) and thanks to the last chapter, when I see that picture I started to see all clear!!!!
There are a lot of hidden message:
1) Seiren is following Kaname...(like we saw in the last chapter Seiren is the only alley to Kaname).
2)Ruka and Kain left Kaname...their roads are going to separate....(I don't know if they will be enemy but I don't really think so...because
3)Ruka (like you can see from the immage) is wearing on her coat a brooch in the form as a butterfly (It's Yuki!!) We know that Ruka said to Kaname that she has going to be Yuki's alley!! And
4) Pay attention at the ring that Ruka is wearing!! xD Is she going to engage with Kain?!?! Wow this sounds great!!
5) Finally you can see a the moon!!! The position of the Moon suggest the crescent's moon (and in the web I saw this interesting meaning of the crescent's Moon:
Only a coincidence?!?!? Mmmhh -.- I don't think so
Last but not least Hino-sama wrote about this image in her art book this:
About her explenation maybe she uses the expression "Loyal submitted" in order to emphasize the "Ruka's betrayal" (if we wanna call in that way...)
Finally what secrets moments she is going to talking about?! About the fact that Kaname wants to kill all the purebloods?! Or there is something behind?!??!