In the secret room, somewhere in Mount Picu.
After fixing the VR Headset, and the laptop, Arthur noticed the Legacy Company's peril, making him remember his secretary, Emilia. Knowing how hard it was to run the world's most successful company, he knew that Emilia wasn't having a good time.
The laptop showed the Legacy Company's servers. One of them allowed connecting to News Station's Broadcast frequency, allowing to make their own announcement whenever. Under normal circumstances, it would be impossible.
However, Arthur's influence broke boundaries between countries, allowing him to do anything.
Seeing the war on the Internet, he couldn't allow Legacy Company to be under fire because of him. He started the Tournament of Champions sneakily when he changed the date between Isaac's and Kalzer's fight.