Between the time that John leaves the airport and arrives at the hotel after chasing the taxi, he has shaved.
When John finds Nadia tied up in the hotel room (after her boyfriend has found out that she is pregnant), he unties her hands, but not her feet (which were tied up), there is a short fight between them, and it is seen that her feet are not tied anymore.
Running through the airport, she has knee-high sandals; going through security, they are now tall boots.
The Russian accents are very poorly pronounced.
When John knocks out Alexei with the guitar it clearly misses by quite some distance and doesn't break.
Sophia lights a cigarette with a disposable lighter in the car as they leave the airport, but the sound is of the lid of a Zippo being flipped open.
John refers to England as an island. Most of England is on one island, the island of Great Britain, but this is shared with Scotland and Wales.
John confesses to 'Nadia' that his house has an ant problem, because he can't find the nest. This is because he's foolishly killing individual ants with an aerosol spray, instead of putting down ant bait. Any foraging worker which finds this 'tasty treat' will take some back to the nest while laying down pheromones. More workers follow the scent trail and so feed the poison to the whole colony, which then dies.