The Clock King suffers from MacGregor's Syndrome, a fictional disease previously mentioned in Batman & Robin (1997), another DC movie title. In that movie Alfred and Nora Fries suffered from the disease. He's getting money for his sister who is suffering from Cystic Fibrosis, although the chance of two siblings contracting 2 unrelated genetic diseases are not very high.
When Officer Lance calls for backup, he uses his designation "Delta Charlie 52" which stands for DC 52. 52 is a weekly American comic book limited series published by DC Comics that debuted on May 10, 2006, one week after the conclusion of the seven-issue Infinite Crisis. DC is the company that created the character of Green Arrow.
The handwriting on the reverse side of Sin's (Bex Taylor-Klaus) picture that Sara Lance (Caity Lotz) removes from her wallet toward the end of this episode says, "Us at the Game May 10, 2008".
Robert Knepper, the actor who portrays Clock King, also appeared in the TV show Prison Break (2005-2009). The two main characters in Prison Break (2005-2009) are played by Wentworth Miller and Dominic Purcell, who play the supervillains Captain Cold and Heat Wave on The Flash (2014-)