Currently Being ModeratedJul 1, 2013 9:01 AM (in response to Tom Wolsky)
Keynote takes complete control over the graphics system when in play mode. As you discovered, application switcher does not function as the card is 'locked' to Keynote. The only thing to do is press the exit key to reveal the other application. Not a good way of doing things when giving a professional presentation!
Hyperlinks would have been useful to launch another application, but they only action a web page or another Keynote file.
Currently Being ModeratedJul 1, 2013 9:08 AM (in response to Gary Scotland)
When Exposé and Dashboard are checked on (off by default) the Cmd-tab application switcher will function to switch applications and return to the slideshow without having to escape it.