Altair doesn't know what exactly a force field is, but if it can hide an entire city he probably won't be a fan. Nor was he a fan of potential mass memory loss. It was too close to how Al Mualim and the Templar Brotherhood wished to control people.

"This city suddenly appeared one day with no explanation, filled with strange apparitions and noises, and instead of avoiding it people live here and host banquets." Altair paused to process what he just said.

"This entire world seems to be made up of things I've never seen before and I don't understand it."