The team escapes the ambush and regroups in a warehouse to tend to Saito, who has been shot. Cobb realizes that experts must have helped Robert militarize his subconscious to protect his mind from unwanted extraction, something Arthur’s research failed to disclose. When Eames suggests killing Saito to wake him up, Cobb tells them they cannot be killed while so heavily sedated, or else they will become stuck in “limbo”—unconstructed dream-space that may take decades to escape. Arthur and Cobb’s mistakes foment distrust in the group, but Cobb insists the only way out of the dream is to continue with the plan.
Cobb demands that Robert open the combination lock to Maurice’s safe, or else he will continue to torture his Uncle Peter. Cobb chains up Peter next to Robert, and Peter is incredulous that Robert does not know the key to Maurice’s combination lock. The two discuss Maurice’s coldness in the wake of Robert’s mother’s death. Peter tells Robert that inside the safe is Maurice’s real will, which will dissolve the company. Robert confides to Peter that his father, Maurice, always regarded him as a disappointment.
Ariadne forces Cobb to confront memories of Mal in his subconscious, concerned that they will grow more volatile as they go deeper into Robert’s dream. Cobb tells her that he and Mal lived together in the “limbo” of a shared dream for 50 years, before deciding they needed to wake up to be with their children. Upon waking, Mal becomes plagued by the feeling that she is still dreaming, telling Cobb they must kill themselves to return to reality. Mal throws herself off a building, framing Cobb for her suicide, forcing him to leave the country. Ariadne tells Cobb that his lingering guilt fuels Mal’s resilience in his subconscious.
Cobb extracts a series of numbers to the combination lock from Robert at gunpoint, and the team leaves the warehouse, piling into a van driven by Yusuf. In the backseat, Cobb, Arthur, and Ariadne fall asleep and enter into the next layer of the dream, where Robert is at a hotel dining with a beautiful young woman, actually Eames in disguise. Posing as a security agent named Mr. Charles, Cobb tells Robert that the woman has stolen his wallet, and that he is in a dream, vulnerable to thought extraction.
Cobb coaches Robert into remembering the scene of the previous dream, in which kidnappers holding his Uncle Peter were trying to solicit combination lock numbers. Peter then appears as a projection and finds Cobb and Robert in a hotel room upstairs. Cobb manipulates Robert into becoming suspicious of Peter’s intentions, and convinces him to enter Peter’s subconscious so they can learn the truth.
The team goes deeper into the third layer of the dream—an arctic fortress—leaving only Arthur behind in the second layer (the hotel), and Yusuf in the first layer (the van), to ward off hostile projections. When Yusuf’s van is attacked and rolls down a bank, the hotel becomes gravitationally unstable. In the tumult, Arthur manages to disarm an intruder. Under heavy bombardment, Yusuf gives the signal for the team’s synchronized “kick”—playing Edith Piaf’s “Non, Je Ne Regrette Rien"—which means Cobb and his team have limited time to infiltrate the fortress. Not expecting the signal so soon, Cobb orders Ariadne to tell the team the quickest route through her labyrinth.
The team misses the first kick when Yusuf crashes the van off a bridge, but Cobb insists they will be able to catch the second kick in twenty minutes, when the van hits the water. As the team rushes to storm the fortress, Arthur searches the hotel for a way to execute a “kick,” given that the van’s freefall has turned the hotel into a zero-gravity environment. Arthur bundles up the floating, sleeping team with rope and herds them into an elevator.
Nolan builds suspense by immediately embroiling Cobb's team in chaos and disaster, spurred on by the unpredictably hostile nature of Robert's projections. As Saito does in his dream in the opening sequence, Robert keeps his innermost secrets stashed away in a safety deposit box, protected by a combination lock. Nolan's film, which abounds with architectural metaphors, uses the object of the "safe" as a symbol for the most intimately guarded contents of dreamers' minds, which may be vulnerable targets for "extraction." In Robert's case, this information involves his relationship with his father Maurice and his uncle Peter.
As the recruitment of Eames suggests, the act of inception is essentially a kind of forgery: the planting of a forged "idea" in a dreaming person's mind. Whereas in Saito's dream Cobb hands over a forgery to conceal his theft, Peter tells Robert that his father's will is inauthentic and that the "real" one is in fact concealed in the safe. Robert's growing distrust of Peter and reconsideration of his father's dying words is the core of the forged emotion that Cobb, Eames, and the others wish to implant in the deepest levels of his mind.
Although Cobb's team's plan is ostensibly to infiltrate Robert's subconscious, they also inadvertently examine Cobb's subconscious, whose projections he has lost control of. Cobb catches a glimpse of his children while dining with Robert in the hotel scene in the dream's second layer, emphasizing that his guilt-induced memories are beginning to encroach on the mission. After Cobb explains to Ariadne that Mal killed herself because she confused dreams with reality, Ariadne warns Cobb that his lingering feelings of guilt may jeopardize the primary goal of the mission, foreshadowing the final act of the film.
As in the film's opening sequence, Nolan cross-cuts between the various simultaneously unfolding layers of the dream in order to create a continuous line of action, as well as track the way disturbances in one layer of the dream can have trickle-down effects in others. For example, when Yusuf backs the van off a bridge into a slow-motion free-fall in the dream's first layer, the gravitational forces cause Arthur to reckon with how to simulate a "kick" in the dream's second layer, which is unfolding more slowly in time. The amplified amount of time it takes Yusuf's van to hit the water—mere seconds in reality—is precisely how long Cobb's team has to perform the inception.
The "kick" that the team uses is the song "Ne, Je Ne Regrette Rien" by Edith Piaf. The song, whose title translates in English to "No, I Regret Nothing," is a thematic counterweight to the feelings of guilt that keep Cobb tethered to memories of his dead wife, Mal. Piaf's song is grounded in the perspective of a lover who has decided to set fire to her memories, both painful and pleasurable, and begin her life anew. The song anticipates the kind of psychological catharsis that Cobb seeks in trying to come to terms with the unresolved feelings of guilt he still has over his wife's suicide.