While 1h1m12s into the film Travis bled from his nose, before starting the car chase through the slums, at 1h4m55s, at the end of the car chase, his nose is perfectly clean.
In the hostage caravan confrontation scene, after Travis comes out of his daze and grabs his bag containing the explosives etc. and gets Linn in the car to pursue, he never actually puts the bag in the car.
The color of the tie of Liam Cunningham's character Wetzler changes in the final scene from yellow to blue.
Travis and Lin stop at the beach with the bullet ridden taxi. The yellow taxi dome is missing with just the bare bulbs visible. At the next night scene the dome is back on the roof with just a part of it missing.
At 33:30, the doctor is supposedly drawing medicine from a vial with a syringe. She picks up a clearly visible full syringe, then just holds it and the vial for about 5 seconds, not even making a hand motion as if she's drawing the fluid.
When Travis is talking to Frank on the pay phone it is clearly out of service as there is nothing on the screen of the pay phone indicating that there is a call in progress.
In the beginning beach scene it said Key West, Florida for its location. There are no mountains in the Florida keys.
At 34 minutes, the doctor prepares to administer a deadly injection to kill Travis. She flicks the syringe with her finger, a technique used to force air bubbles to the top of the liquid that can then be pushed out by advancing the plunger slightly.. This is done to minimize discomfort or pain during the injection. Yet she's already intent on killing him, making her action frivolous and unnecessary.