Also, probably didn't trust an understandably devasted and out of sorts Storen to not walk Motte.
Well, I think the idea is that walking Kozma would have forced them to pinch hit for Motte. The back up catcher was the only hitter left, and no one was warming in their bullpen, so they would had to get someone ready quickly, and we would have gotten to face someone other than Motte in the 9th. It all sounds good in hindsight, but walking someone intentionally when you already have two strikes is just something that I've never seen done, and would be an awfully hard call to make. As you say, you take a chance on walking in the pinch hitter, and just in terms of giving up a hit, I have to think the batter with a fresh count has a better expected average than Kozma with 2 strikes.
Of course, by then the game was already tied, and what we really should be rankled about was the inability to protect a 6-0 lead over the whole 4th-9th innings.