Grace Under Pressure

"Grace Under Pressure" is the fourteenth episode of the second season of Stargate Atlantis.

Plot
Rodney McKay and Captain Griffin are flying from the mainland back to Atlantis. Rodney is worried about the ship, considering it's the first flight its had since it was shot down in "Condemned". All seems to be going well until they experience a malfunction and the ship crashes into the ocean.

About an hour later, Griffin and McKay wake up to Radek Zelenka's relentless radio calls. McKay had suffered a blow to his forehead and was bleeding. They realize that the ship had sunk about 1200 feet and was sinking at the rate of 20 feet a minute. Suddenly the windshield started to give way to the pressure of the ocean. Rodney immediately heads for the rear compartment and tries to seal the bulkheads, except the switch was damaged. Leaving Rodney in the rear compartment, Griffin stumbled into the front compartment and pushed the switch right before the windshield shattered, sacrificing himself. Griffin is (most likely) crushed by the intense water pressure. Up on the surface, Radek tries to pinpoint McKay's location while John Sheppard tries to find a way to lift the sinking Puddle Jumper from the ocean.

Back in the Jumper, Rodney tries to stave off his claustrophobia and save himself. Turning on the emergency transmitter, he discovers that he only has 3 hours of power left in the Jumper because the inertial dampeners were using up most of the power. Rodney immediately commits to the idea of doom.

Suddenly, Samantha Carter appears to McKay in his hallucinations. After taking a moment to take in the fact that he's hallucinating, Carter explains to him that she's there as a hallucination to help him and due to the rather bad concussion on his head.

Back in Atlantis, John suddenly has a bright idea. If they can turn the Jumper's cloak into a shield like the Atlantis shield was turned into a cloak, they could dive even deeper. Zelenka informs him that it would take up a lot of power and shutting down anything they don't need would take hours to reconfigure. John suggests that they make the changes as they get down there.

Rodney's Jumper hits the bottom. Sadly, Sam points to the bottom of the Jumper. The Jumper is taking in water.

Finally onto something, Zelenka manages to get the shield up and running. Under the pressure of the ocean, the shield is continually draining power. They have about 30 minutes if the shield continues to drain power.

Sheppard notices that the monster seems to be circling the same area over and over again, which means it probably found something interesting. They find the Jumper beneath the area the monster was circling. Radek realizes that they can extend the shield between the two Jumpers and just walk between them. They retrieve Rodney from Jumper 6 and as they return to theirs, the gigantic whale creature majestically swims overhead. Setting him down in the rescue ship, Rodney looks to Sam, who is smiling and waving.

Background notes

 * The sea monster species is later named Flagisallus and it makes a reappearance in the later episode, Echoes.
 * "Grace Under Pressure" was nominated for an Emmy Award for Outstanding Music Composition For A Series (Dramatic Underscore).
 * The Season 7 Stargate SG-1 episode Grace involves a similar situation where Samantha Carter is Trapped aboard the Prometheus and has several hallucinations. It is likely that the title of this episode is a reference to that one (Grace) and to the fact the Jumper is at the bottom of the ocean (Under Pressure).
 * Ronon Dex, Teyla Emmagan & Carson Beckett do not make an appearance in this episode.
 * Rodney McKay's hallucination of Samantha Carter is mentioned in an episode of Stargate SG-1, The Pegasus Project
 * In a later episode of the season, Jumper 6 is mentioned. This is most likely one of the new jumpers from The Tower as opposed to the damaged jumper at the bottom of the ocean, as Zelenka claimed it would be near impossible to raise given it's depth and the fact that it would be full of water once the rescue jumper's shield was removed.
 * McKay refers to the hallucination of Carter as "Lieutenant Colonel Siren" when she tries to distract him. This is a reference to mythological Sea Sirens which would tempt sailors towards them causing their ships to crash onto rocks.