Benson says to Stuckey "If you hear hoof beats in Central Park, don't think zebras." This is a famous medical aphorism credited to Dr. Theodore Woodward, from which the episode gets its name; "zebra" is medical slang for arriving at an exotic or extravagant diagnosis, when a more commonplace explanation is more likely.
The character Gwen Munch (Carol Kane ) originated on Homicide (1993) as the ex-wife of John Munch (Richard Belzer). John discovers on a cross over with Law & Order (1990) that Gwen had an affair with Lennie Briscoe (Jerry Orbach ) after he and Gwen were divorced.
Richard Belzer (1944-2023), the actor who portrays John Munch, in real-life was married three times, with his first two ending in divorce. He was also a staunch conspiracy theorist, and a published author of his theories on matters such as the JFK assassination, Marilyn Monroe, UFO's, Elvis Presley, Malaysia Airlines Flight 370, and Princess Diana. He authored six books on conspiracy theories.
This is the first of two episodes of the entire series to air in the month of June. The next time this happens for the season twenty-two finale, Wolves in Sheep's Clothing (2021), which aired eleven years and one day later.
Det. Tutuola (Ice-T ) says "They're Skells". Skell refers to a person who is homeless, vagrant or derelict. It is often used to describe such a person who is habitually engaged in small-time criminal activity. The term originated in the 1960s, in New York, USA. The term has been used in several American TV shows, by police officer characters.