Review the original item:
Fighting the urge to crawl under her desk, Adriana looked at the
clock,
a half hour of class remained, more than enough time to do her poorly
prepared, ten-minute speech.
You wanted to fix it this way:
Fighting the urge to crawl under her desk, Adriana looked at the
clock,
so a half hour of class remained, more than enough time to do her
poorly prepared, ten-minute speech.
A comma with a coordinating conjunction like so is a perfectly legal way to correct a comma splice. However, you must choose a logical coordinating conjunction.
So indicates result; it means the same thing as the transitional phrase as a result. Such a transition in the example above makes no sense.
You might want to consult the rules for fixing comma splices and fused sentences.