You can abort an experiment at any moment via code snippets. To do it, navigate to the 'Experiment' ribbon tab and find 'Abort Run Now' property in the property panel there. Select the property and create a proxy variable (in order to access it in the snippets). Then, place the following code in a selected snippet:
If you place this code in the 'After Onset' snippet of the final event in your experiment, the latter exits back to the EventIDE designer as soon, as the finale event is reached.