If Flash froze for 15 minutes (I'm more inclined to believe 5), that's either a Flash or computer issue. It can happen to me when my laptop is using too much of its resources and gets warm enough that it slows down. Flash is incredibly prone to freezing up/crashing.
When it comes to connection issues, you won't be able to spin the card and should be able to reload the page to get the button back. However, I wouldn't play with an iffy connection since it can and will cause both desynchs and your drawn cards to sometimes disappear at the point in time when it saves.