It was a fiction problem.
Vraton’s Bookstore
The variant for Ouroboros, AD Doug, PhD, plants a copy of his science-fiction book in a Pasadena bookstore and then attempts to purchase it.
The production found and used a real bookstore in London, called West End Lane Books, and redecorated it slightly as this Pasadena bookstore.
MAP
Street View
AD Doug’s Workshop
Loki appears later at AD Doug’s workshop, which appears to have been built from an abandoned power plant in the hills outside Pasadena.
While nothing like this exists in Pasadena, the exterior appears to be stock footage of an abandoned power plant, which is at an unknown location. The interiors of the workshop were filmed at Pinewood Studios and are a revamped version of the TVA Repairs & Advancements room where OB works.
(Loki S02E05, 2023)
MCU: Location Scout 