The trap should do the trick! Let us know how it goes!
All 5 of my cats are indoor cats and I'll take them outside for like 10-20 min. 3-4 times a week (they're never by themselves, I'm so protective over them!). I would go crazy if one got out and I couldn't find it, they're my life! Its good you know where he is though, and he didn't totally run away, that would be scary.