When detective Karaman shows Emily the pictures and the sketches of he murdered man, you can see the man stabbed on the left side of the neck on the picture (as really happened), but on the right side of the neck on both sketches.
During the attempt on Emily's life her hair is in a ponytail, then it's down, then it's up in a ponytail again. This happens a few times during the fight.
When David takes out the shoe box with the money in it it has a rubber band around it. It did NOT have a rubber band around the box when Steven had it in the bag.
When Steven and Emily arrive at Emily's family home on the morning after the attack, they are still wearing the same clothes from the night before, have clearly been up all night yet Steven is clean shaven.
Emily is wearing a white blouse and pearls the first day we see her. The next day, in the delegates arena, she is wearing the same outfit. However, when we see her on the train headed to David's at lunch time, her outfit and jewelry are different.
Emily supposedly works for the UN, and, indeed, we see her in her office on one scene. However, towards the beginning of the movie, she is sitting directly behind the US Ambassador to the UN, and even passes the Ambassador information about the delegate of another country. UN staff would never do either of those things - they would only happen if Emily worked for the US State Department, not the UN.
When Emily opens the door to apt. 219 - sealed with yellow crime scene tape - she inserts the key into the deadbolt and turns it counterclockwise. Based on the door configuration this would have LOCKED the deadbolt but it opens smoothly...
In the end credits where 4 "delegates" - Croatian, Russian, French & African - are listed, the 1st one is misspelled "Croation."
When Emily whispers over the shoulder of the US Ambassador about a reused United Nations speech, the man giving the speech is the delegate from Yugoslavia, a country that ceased to exist after 1992.
Since the 1990s and the elimination of the "Montrealer", Amtrak does not offer night service to Montreal, nor are there sleeper cars on the trains. The only overland train route to that city on Amtrak is the "Adirondack", a morning train that is all coach seats.
Even though Elliot and the companies knew Stephen's company was under investigation, they continued to do business with him because Stephen and his company haven't been convicted of anything.
Steven tells David, David would receive fifteen years without parole if David were to inform the police on Steven's plan to have Emily killed. Even though only a judge could determine the sentencing, Steven was only intimidating him with a long prison sentence in order to convince him to agree to the murder plan.
The police dusted the house, elevator, access, etc because at that point they hadn't determined how the intruder entered the building. The police has to follow standard police procedure such as questioning Emily and Steven.
After the scene, where Steven opens a door for policemen, a camera pans down the spiral stairs. You can see two officers down there on the stairs obviously waiting for director's command and then start moving simultaneously.
On the subway, the conductor says "Greenpoint next stop. Transfer to the A, D and F upstairs." The Greenpoint Avenue Station in Brooklyn is on the G line and it has no transfer point to any of these three trains.
After Steven kills David, he only takes the 400K in the shoe box that he just gave him & not the 100K that is most likely in his David's backpack.
While Karaman is questioning Steven in the kitchen, he points out that Steven's footprints are visible all around the body in the blood. We also have seen that when Emily left the kitchen she left a trail of bloody footprints. However, when Steven runs to the door to fix the lock, he miraculously leaves no bloody prints on the floor.
When Michael Douglas leaves the apt to play poker with his friends, he was driving a Mercedez Benz. You can clearly see in the dashboard 7:30pm, while at the same time the killer enters the building. It doesn't looks like the killer is going to spend 2:30 hours waiting for the 10pm call.
When the hired masked assassin tries to kill Emily & fails by being killed himself,neither her or Stephen take his mask off to check who it is.It would be the first thing to do in actual circumstances.
If David had a reservation to go to Canada to cross international lines he would have to use his legal name to go through customs. Therefore when the travel agent calls to confirm his reservation she would request to speak to "Winston", which is his legal name and not "David" which is his alias.
When Emily brought her suspicions of Steven's possible involvement in her attempted murder to Mohamed Karaman, she should have told him Steven told her he was going to call her before he left for the poker game.
David wouldn't have been allowed to enter Canada and cross international lines with a gun and $400,000.00 in cash.
Emily shouldn't become irritated when the phone rang during her bath because Steven told her he was going to call before he left for the poker game.
When Karaman receives a personal phone call while Emily is being questioned, he should know to leave the room because it's unprofessional.