In the Stargate Atlantis: Legacy novels, this specific Queen is identified as Cold Amber and revealed to be the original "Queen Death".
The Queen activates a self-destruct sequence on her crashed cruiser. Because the facility sits on a very thin part of the planetary crust, the resulting explosion would trigger a volcanic cataclysm capable of destroying the platform and Atlantis itself.
Teyla senses the Wraith presence immediately upon arrival. The Queen eventually takes control of Teyla's mind to use her as a puppet to facilitate her escape.
This guide covers , the 18th episode of Stargate Atlantis Season 3. In this atmospheric, "underwater-themed" thriller, the team discovers an Ancient drilling facility deep beneath the Lantean ocean, only to find they aren't alone. Episode Overview
Sheppard and McKay use 10,000-year-old Ancient diving suits to reach the cruiser. Teyla uses a mental "counter-bluff" to trick the Queen into deactivating the self-destruct codes, allowing Sheppard and McKay to eliminate the Queen and save the city. Fun Facts & Trivia
Fans often note that Teyla is psychicly compromised or "taken over" in the 18th episode of every season up to this point.