LOL He looks so reluctant. I always assumed it was because he'd never been through a wormhole to me. The way he closes his eyes before stepping through definitely says inexperience to me.

Plus, it would have been smart if the SGC had sent him through the gate before the big mission. But as we all know from their long-term planning re: food and the like, they aren't so good at being long-term, smart thinkers.