The real Doomsday Clock is maintained by the members of The Bulletin of the Atomic Scientists' Science and Security Board. As of May 2017, the actual setting is 2.5 minutes to midnight.
The Doctor's sonic sunglasses show that Bill is a 26 year old female who weighs 130.2 pounds, is 167.6 cm tall, has a heart rate of 79 bpm and a body temperature of 37.6 degrees C.
Doomsday Clock update: As of January 2020, it is set at 100 seconds (1 minute 40 seconds) before midnight; which is the closest to midnight the clock has ever been set since it's foundation in 1947. In the immortal words of P.F. Sloan, "We're on the eve of destruction."
"Enzyme EC 31" tank seen in the lab is probably based on the real Enzyme Comission (EC) number system for classifying enzymes based on the chemical reactions they catalyze. However the real codes are in the form of four numbers separated by periods.
The theme of the 10th Doctor can be heard in several scenes.