lepr like that is supposed to be run continuously, on every tick.
"On key pressed" is a triggered event, it happens once, that's why your object only moves a tiny bit. Besides, you must use dt in lerp expression if you want it to work correctly at different framerates.
You can change your code like this:
On Q pressed: Set Action to true
System is Action: dot set position to (lerp.....
But you also need the way to stop the lerp when the dot reaches the player, otherwise it will be chasing it forever.
I suggest using MoveTo or Tween behavior instead, it will be much easier.