Oh no, what a nightmare.
As the other member`s have said, Syrians are solitary hamsters and should never be housed together unless it`s a male and a female for breeding purposes by a breeder. Did your room mate buy the hamsters recently from a shop or what? Shame he/she didn`t find this forum when they originally got the Syrians or this may have been prevented.
The remaining Syrian should be fine, but I strongly suggest your room mate joins, or at least reads some of the sections on here to find out more about Syrian hamsters and the best way to house and keep them.