Factual error: Bryan tells Kim to go to the US Embassy if he doesn't return in 5 minutes, and enters "US Embassy" into the GPS. Later there is a chase scene that ends at a building with "United States Embassy" on the signage. This is impossible unless they drove about 6 hours to Ankara, the capital city. Istanbul has only a US Consulate (albeit a very impressive one).
Factual error: Liam Neeson asks his daughter to set the grenade off and counts to 4 after that. He then calculates the approximate distance of the hotel from the place he was taken to, by multiplying the speed of sound (0.34 km/s) by the time taken for the sound to reach him (~4 seconds). Given those numbers, the distance between him and his daughter is about 1.36 km, whereas he calculates it to be 4.5 km. He also makes a minor slip up in using "circumference" instead of "diameter" when she draws the larger circle, but that's incidental to the real mistake here. (00:43:00 - 00:44:00)
Factual error: In the end credits, when the list of songs appears, look at the credit for Alex Clare's song "Too Close". His name is misspelled as Alex Claire, a very noticeable typo. (01:30:40)