Theo watched Zach cross his heart but far from a motion to keep a promise, saw it as something else, although like the motion he had learned the other thing in childhood too. He traced over the cross over Zach's heart and kept going, lines and patterns etched by his fingertip before he stopped to put his hand flat against Zach's chest and murmur something that sounded Russian by way of Italy.
"Sealed." he said, seeming pleased with the nothing he had done - no wand, no magic. There were even dampers against him in this place to stop any accidental wild magic leaks. "It's called Theodore."