In what will become a character trademark on both TNG and Star Trek: Deep Space Nine (1993), Miles O'Brien reports to Sick Bay after injuring his shoulder in a Holodeck kayak simulation. It's not his first accident, because Wesley asks "Kayaking again?"
The craft seen in the shuttle bay when John Doe is attempting to leave the Enterprise is named the "El-Baz." The craft's name was a tribute to real-life geologist Farouk Elbaz. While working for NASA, Dr. El-Baz was instrumental in selecting the location for and planning the landing of the Apollo 11 Lunar Excursion Module. He also trained astronauts for subsequent Apollo missions in how to observe and report geology.
This episode shows the first appearance of the large laboratory set, later re-used as stellar cartography and a number of other laboratories.
Doctor Crusher is assisted by Nurse Temple, named as a tribute to Nurse Chapel in Original Star Trek who was played by Majel Barrett, Temple and Chapel having a similar meaning.
Though only seen briefly, John Doe has actually lost his left arm during the crash. It is apparently later replaced with an artificial arm; however, spoken dialogue suggests it was stored in stasis and later reattached. Furthermore parts of his facial skin and skull have been torn off during his crash, revealing his brain and his molars.