Board Thread:New on Ben 10 Wiki/@comment-37390956-20181110111416/@comment-28802873-20181117093700

I think that's easy to figure out when someone, like say, Azmuth or Myaxx, looking for samples, tells him what it does and Zs'Skayr tries to take it for himself Read answer above. Also, you don't need to know who made it to steal it and use it for your own gain. He would know if he was locked inside. He would know when Ben unlocks him, or while he's stuck inside the watch.
 * What is Omnitrix?
 * Who created the Omnitrix
 * Where is Omnitrix?
 * Who is wearing the Omnitrix?

Also, Gax is still inside the Omnitrix, locked, and Ben hasn't seen him, but he saw hundreds of pods. Ghostfreak could be in one of those, with Zs'Skayr stuck in it like Vilgax's power was stuck as Gax.

Literally, he could have the same reasons as OG to be stuck inside the Omnitrix, and it'd still work.