Hello Goodbye

River's grandfather in his confused state asks River who's after him. He asks "is it Karla"? Karla is the main antagonist in John Le Carre's "Tinker Tailor Soldier Spy" which starred Gary Oldman in the 2011 version.

River is locked in the boot/trunk of a passerby's car and driven away.

However, since 2002, all cars have an interior trunk release lever or button which is easy to locate, being either a glow-in-the-dark pull cord or button, or lit with an interior light (easy enough for children to find as this is who it was designed for, to stop them getting locked into the back of cars).

River would be aware of this feature yet for some unexplained reason chooses not to use it at any time. Even though he may subsequently be prevented from escaping, he would at least try or maybe alert other people (e.g. following cars), to his presence.