The suspect in the New York explosions, surprisingly enough, does have a Muslim name, Ahmad Khan Rahami, but the police have no idea what the motive might be. I imagine there will be more of these attacks, in the USA and elsewhere. Whether it is intended or not (and it probably is) it will help Donald Trump and hurt Mrs Clinton. It could clinch the election, though Donald Trump has the Big Mo already.
On a subconscious, irrational level, an old lady fainting at the commemoration of September 11th will, for some voters, not inspire confidence in her as Commander-in-Chief.