They're level 4, in 4e. If ANYONE had done a perception check, they would have noticed the control panel. The rogue has a +12 in thievery (skills have been streamlined, but I knew exactly what you meant.).

I think I shouldn't have dropped the DC, but I will do the math to give him a 75% chance vs a 50% for next time. I'm just so used to these guys maxxing out their characters that it didn't occur to me to make a backup plan for failure.