dropbox.com/s/utr7vnkx9ldzzdx/dramaticzoomexample.capx
When doing actions over time, use a timer behavior. For smooth motion, you want to use lerp.
Construct 3 has a new Tween plugin that makes this sort of action easier to accomplish.
What I'm doing here is using lerp between two points, using the time elapsed over total time as my progress amount.
If you want the effect to happen before the object actually collides, you can use an invisible helper object that is pinned ahead of the bullet to trigger the effect instead.