(Sheppard walks through the wall into the Janus' lab. It's obviously his first visit because he stares back at the wall in amazement.)
Sheppard: Wow! That's pretty cool!
(McKay, Daniel and various scientists are inside the lab.)
McKay: Harmonic resonance.
Sheppard: Yeah, I was told, but what happens if the sound goes off and you're in the middle of the wall?
McKay: Well, the wall would break apart your body.
Sheppard: (nervously) Maybe we should, uh...
McKay: I've set up a sub-sonic tone generator outside. The wall is now permanently open. Don't worry.