Stealth drawing accurate diagrams after briefly seeing the device

St. George peered over Stealth’s shoulder. “Almost done?”
“I believe so,” she said.
“You did all that from memory?”
“Of course.”
“That’s kind of amazing.”
“Thank you, George.” The cloaked woman set the diagram in front of Danielle.

Excerpt From Ex-Patriots, pg 324
Peter Clines
https://books.apple.com/us/book/ex-patriots/id585738393