Caitlin is brought by Peter into the future and is left there. She is then deported to Ireland and is no longer mentioned in the series.
The syringe used in this episode is made of glass. Glass syringes were used until the plastic syringe gained widespread use. Glass syringes are still used presently for some medications that might interact with plastic or for people with latex allergies.
This series shows a lot of outdated tech. Up until the second season (2007) people were using so-called "feature phones" and pocket-sized digital cameras, both of which are seen in this episode. It was this year, 2007, that Apple introduced the iPhone which was followed not long after by Android phones and the iPad, which revolutionized the world of portable devices.
With 9.87 million viewers, this was the lowest rated episode in the second season.
The explosion of White Beard's camp blew out a massive nearby transformer, resulting in nearly 7,000 residences losing power.