Table within a table vertically center-aligns paragraphs in neighboring cells instead of leaving them at the top

Table within a table vertically center-aligns paragraphs in neighboring
cells instead of leaving them at the top

I nested a table inside of my table like this:
\begin{tabular}{p{1in}||p{5in}}
\hline
This should be on top. & \begin{tabular}{@{\extracolsep{\fill}}lr}
Thing1 & Thing2 \\
Thing3 & Thing4 \\
Thing5 & Thing6 \\
Thing7 & Thing8 \\
\end{tabular} \\
\hline
\end{tabular}
and it looks like this:

but since This should be on top is in a p cell, shouldn't it stay up on
top? How can it be made to look like this? :