Danny had been knocked aside by the ecto-guns blast, but intangibility aside, he was still human, and thus not as hurt as he might've been. Which was why he was able to fly through Tim's hand and grab the Kryptonite.

"Huh. Glowing green rock." Danny said, hovering away from the group. "Looks kinda radioactive....five bucks says I can find a statue made of lead to shove this thing into. Any takers?"