Why didn't Helen trying brake stop limo?
Dead man keep drive to bridge collapse. Why don't she trying stop limo?
I assumed it was because there was a partition separating the driver from the passengers. Presumably she either couldn't physically climb through or it was closed from the drivers side. Perhaps that was why she went for the gun on the roof, so that she could shoot out the glass and climb through, but that plan didn't work.
...and a pair of titties that make you wanna stand up and beg for buttermilk