It was shocking, but Rex shook that moment off his mind as there was nothing he could do.
No need for him to worry about something that was way out of his hands.
Despite how unexpected and terrifying that moment was, for that Executor to sense them probing the past like that, there's still no direct contact. He didn't attack Rex and Kei Xun, but only gave a warning that he would not stand being probed again.
Rex wasn't that worried about what happened.
Considering the method of contact, there should be no chance for the Executor to attack him right now.
In fact, Rex was rather thankful for what the Executor did.
Above all, that incident reminded him that there are still many enemies out there that he needed to deal with before the pack and the people he cared for can finally be safe. Healing Nivellen would not be the finish line; there's still more.
Rex exhaled roughly through his nostrils.
