Won't happen. TCC supposedly has a critical shortage of space (at least that is what it tells the employees).
If RadioShack does close its corporate headquarters then Tarrant County College would probably just take over the rest of the complex.
Which could mean that whatever is in the May Owen Center can pack up and move in... which would quickly open up that space for the Omni.
Back in 2014, the district moved about 150 employees from Trinity River up to Alliance Airport due to what they called "a critical shortage of space". So bclaridge is correct that TCC will probably just take over the campus.
However, I doubt they will leave the MOC. At the April 16, 2015 board meeting they authorized the chancellor to develop a "request for interest, use, development, or lease" for the MOC (the video is still available on the TCC website in the board meeting archives - it was one of the items mentioned after they came out of closed session). It was never publicly mentioned again, so I assume nothing ever came of it. If they wanted to get rid of the MOC, they probably would have by now.