The name Charles Hinton is a reference to British mathematician Charles Howard Hinton. He was known for his theory on the fourth dimension and also coined the term "tesseract" for the four-dimensional analog of the cube.
This features the second one-shot fight sequence on the show. Both were performed by Chloe Bennet without a stunt double and were directed by Kevin Tancharoen.
The character Rowan Hamilton is presumably named after the Irish mathematician William Rowan Hamilton who was responsible for many breakthroughs in science and mathematics. In pure mathematics, he is best known as the inventor of quaternions.
The character Edwin Abbott is named after the 19th-century teacher and theologian Edwin A. Abbott who wrote the book "Flatland," which uses a similar metaphor to explain the mathematical theory of time and space that Fitz uses as an explanation for the team.
"Spacetime" originally aired on ABC on April 5, 2016, and according to Nielsen Media Research, was watched by 2.81 million viewers.