Spidey would dodge all of the bullets. While homing in on the assassin. Sniper rifles take time for the bullet to reach it's target. And her slow down time ability only works in close range encounters effectively.
Spidey's Movie feats had him slow down time whenever Spider Sense activated ANYWAYS. And Spider Sense slo mo beats adrenaline anyday.
The whole distance thing is wierd for Fox could just escape and try again later....but considering this is a forum fight it has to end there so as she shoots at him...hopelessly missing everytime Spidey eventually smashes through the window and captures her.
The whole saving civilians thing is pointless. Parker can't save them so he goes straight for the offender. Rather quickly.