I see lots of jokes regarding this going bad. From a serious scientific perspective, it could go bad and kill lots of people. I would need to know more about how it seeks out the infected cells to be sure but: Cellular mutation is a fascinating and a complete mystery really. There is no specific gene that does something with a very rare exception (as what's found in the case of Sickle Cell Anemia, and a total of only 2% of all diseases known to have a genetic component). That being said, I would like to know exactly how the identifier works, and what prevents it from seeking out non infected cells. I mean, it is supposedly good against "any" virus. A group genetic mutation could all of the suddenly make it seek out and destroy healthy cells as well. Though, on the genetic landscape, this is very unlikely. A greater likelyhood is that it would adapt to whatever protocol they come up with and would be left at square one. Though, if they used this only on common and usually non lethal viruses only, and they viruses adapted, then we would just have more Flu (for example) that is resistant to this. I don't get the Flu, my immune system is completely top notch, and this would probably not affect me at all. We all get Ebola though, haha.
On the other side, I certainly didn't go to MIT. I am just a huge Biology nerd... thinking of pursuing an even higher education in the field Epigenetics. So, this is fascinating.