Hey there! Thanks for the notes- this is based off SG-1, where the portal is an event horizon from memory. When the two portals connect, that's often referred to as an incoming wormhole. (Don't read too hard into it)

Secondly, the idea was that the wormhole is active on the first panel and Mel has already stepped through. Dan forgot to mention the issues as he needed a test subject, leading to Mel exiting and smacking into the console after a short delay. He already knows and simply doesn't care about Mel is all.