King Mustard

I was wiping a drive using CCleaner and decided to try to see right-click on CCleaner in the system tray and choose Exit. The icon goes away from the system tray but the program still runs. My drive wipe has not yet completed, so I am unsure what will happen when it finishes. Perhaps the program will close? Ideally, whilst a drive wipe is happening, choosing Exit from the system tray icon would display a message asking if you would like to cancel the wipe or not.

Is this normal? I'm only using a Simple Pass (whole drive). I want to sell the drive, therefore I want it wiped. But I don't fancy waiting this long :/