Here is the original item:
Circling the parking lot,
(A) Dominique
searched for an empty space close to the mall
entrance (B)
so that an afternoon thunderstorm would not drench
her (C)
while she was loaded down with good buys.
You wanted to do this:
Circling the parking lot, Dominique searched
for an empty space close to the mall entrance so that an afternoon thunderstorm
would not drench her,
while she was loaded down with good buys.
Adding a comma after her is an error. While she was loaded down with good buys is a subordinate clause. This type of clause will usually require no punctuation when it concludes a sentence.
You might want to review the rules.