Here's a few nit-picks and then I'll try to give you some advice:
“Stop!” A stranger's voice yelled from the bridge. His feet pounded loudly on the ground as he ran toward me, “dDon’t do it!”
“I. Just. Want. You. To. Know,” he shouted, “That. I. Have. A. Great. Fear. Of. Heights.”This format isn't necessary and looks really odd. Find a better way to convey it. Maybe tag a line on that explains how he speaks or something.
I huffed, what’s so great about that? I thought, annoyed by his intrusion on my time of escape. My eyes rolled and Igrindedground my teeth, caging my words inside my mouth, knowing that I’d regret saying them if I let them out. Reason told me that he was only trying to help; it was just so irritating that he couldn’t understand.
We laughed together about the ridiculousness of the situation we had somehow both become involved in. It wasn’t longuntilbefore I gave in to the stranger’s fears and climbed back over. I, of course, had to help him as he attempted to do the same, although at a much slower and cautious rate.
“You don’t strike me as someone who talks about things like the bridge with your friends,” he guessed, “so I don’t suppose you’ll be needing that stranger's name after all - though crazy he was. Maybe he should remain anonymous?”
Dialogue
The best lines in history are short, snappy, memorable and just generally concise. I found that your dialogue was a little too long winded and got wrapped up in itself so I had to read it two or three times before I really got what the characters were saying. Try to come some of those longer speeches down just a little. Keep the wit but make it snappier.
Originality
See what you can do to make this scene more unique. At the moment, it's the typical, first person not really committing suicide, but second person thinks they are and is scared of heights but tries to save them. Then first person must rescue second person etc. It's been done way too many times so there's not enough interest here plot wise and your characters aren't compelling enough to carry the section. The only time an old plot works well is when the characters are particularly awesome/ refreshing or there's enough twists and good lines to still keep the reader thinking/ generally entertained.
Overall
Not as strong as your prologue but as I said, you do engage with the reader and there was some building of Sophie's character. It's a shame the guy was such a cardboard cut-out. I think you need to work on him, do something with the dialogue in general and try to put your own spin on the plot line. Hope this helps a little,
Heather xxx
