Remember the stein job

Arthur remembers the Stein Job...

Cobb: We run with Mr. Charles like we did on the Stein job.

Eames: So you've done it before?

Arthur: Yeah, and it didn't work. The subject realized he was dreaming and his subconscious tore us to pieces.

Eames: Excellent. But you learned a lot, right?

The Stein Extraction Job was a job undertaken by Arthur and Cobb. Cobb used the "Mr. Charles" tactic, but it failed when the subject realized that he was dreaming, and his subconscious tore the team to pieces.