The dream's second layer is a hotel lobby, where Eames poses as a female thief to distract Robert.
Cobb, himself posing as a security expert, pretends to help Robert by alerting him to the robbery and making him aware of the fact he’s in a dream. This deliberately brings the wrath of Fischer’s subconscious projections on them.
Cobb manipulates Robert into becoming suspicious of the motives of his Uncle Peter, whom he accuses of working with the kidnappers and wanting the alternate will for himself.
Because of this, the team is pursued through the hotel, so Arthur stays behind to fight off the projections while everyone else goes into the next dream level.