Hi,
You have sequence turned on.
You can see this on the lines between the actions. (On the left side, you will see a 'v' form.)
You can turn this off by right clicking on an and deselect Action sequence.
When sequence is on, the next action will only start when the previous one is finished.
Get mouse button down is using every frame, so it will not end until the mouse button is pressed.
When sequence is off, the action will all start from top till bottom.
But without waiting for the previous one to finish.