Fire generation probably doesn't work very well in the vacuum of space anyway, since there'd be no oxygen for it to burn -- aside from what I'd carry with me which I'd be using.

[He's just going to ignore the fake-outside alternative in favor of talking about Grif's power, 'kay? 'Kay.

The sand you were just running on isn't flat either, the principle is roughly the same. You'd send up a spray of water, but your feet might touch the water so briefly that there simply isn't enough time for your feet to break the surface tension of the water.