The show already proved that even if you do not get a deal, you still get benefits from the apresentation.
If we do a little bit of math, it's easy to see that it's not an outrageous amount. How much does it costs 10 minutes in prime time? And even, probably, you business is gonna grow even more than the 5% that they take out.
They don't "take out" anything, they will own 5% of all that future growth too.
Five percent of Facebook is (in theory) worth ~5 billion, while ABC itself is worth around 3-4 billion. If Instagram had been on the show they would have gotten $50 million a few weeks ago. For half a million dollars you can buy your own 30s commercial, and that's a bad deal for nearly every startup in the world.
If we do a little bit of math, it's easy to see that it's not an outrageous amount. How much does it costs 10 minutes in prime time? And even, probably, you business is gonna grow even more than the 5% that they take out.