\documentclass[../script.tex]{subfiles}
%! TEX root = ../../script.tex

\begin{document}
    \chapter{Real Analysis: Part II}
    \minitoc
    \vspace*{\fill}\par
    \pagebreak  

    \subfile{sections/lims_and_funcs.tex}
    \subfile{sections/diff_calc.tex}
\end{document}