When interrogating the student on the school stage, the set is decorated like a police interrogation room. The words on the door behind the Librarians start out backwards and then flip midway through the scene.
You can't normally just open an app in an editor and see the source code. The executable on the phone would have been compiled from the source code into some kind of machine code that the phone's operating system can deal with and reversing that process is by no means straightforward. If the programmer doesn't release the source code, then usually it is easier to hack him and steal it.
The science girl that Ezekiel talks to says "sea otters" are dangerous but the models she has on her display are not the species known as sea otters.
In the beginning, Cassandra asks Jenkins to "fire up the door" because they're going to Chi-town, a nickname for Chicago. She incorrectly pronounced the 1st syllable with a hard Ch sound (as in chicken). It's actually pronounced "Shy-town," with a soft Ch sound.