Complex sentence: Days later, once "Specimen 6" is fully grown, during an observation of its abilities, it is told by its Queen, which is also imprisoned, to escape, but it is gassed and recaptured.
Split into simpler sentences: Days later, once "Specimen 6" is fully grown. During an observation of its abilities, it is told by its Queen, which is also imprisoned, to escape, but it is gassed and recaptured.