Tip if you want to watch, and don't feel like timing the finisher at the same time, is to open 2 tabs.
Stop one on the green bars before you click off, just before finishing, and then put it in the background.
Open a new tab, and put it slightly over, but just enough so you can still see the "FINISH" button's edge of the other tab.
Play the top tab normally, then move mouse over and click the pink button's edge on back tab to finish when you feel like it.