Quarantine - [s4e13]

: The team eventually learns there is no real contagion; the quarantine was a system malfunction caused by an atmospheric anomaly.

: This episode builds the early romantic tension between Ronon and Dr. Keller. "Stargate: Atlantis" Quarantine (TV Episode 2008) - IMDb [S4E13] Quarantine

: To stop the distress beacon, Sheppard performs a dangerous external climb up the side of the city's central spire to reach the control room. : The team eventually learns there is no

: Stuck in the infirmary. Ronon injures himself further by trying to pry open the doors with an IV pole, leading to a tense bonding moment as Keller treats him. The Climax & Resolution "Stargate: Atlantis" Quarantine (TV Episode 2008) - IMDb

: Trapped in the botany lab. McKay is about to propose with a diamond ring when the lockdown occurs. Due to his nervous nature, he eventually convinces himself he has contracted a fatal contagion.

: Confined in a transporter (lift) with only a laptop. Their attempts to bypass the system lead to friction, especially when Zelenka accidentally shorts out a circuit.