Board Thread:General Discussion/@comment-94.8.59.184-20140809221526/@comment-25086632-20151121071035

It just straight up doesn't make sense narrativelly speaking that we'd see Ozpin's desk get infected, and then have Cinder talking about a new access point in conjunction with Ironwood's face on her scroll.

So logically from an entirely meta point of view (not even counting the fact that in-world it wouldn't make sense for Ironwood to infect Ozpin's desk because Beacon Tower is already infected), it had to be Ironwood's scroll being infected.