...

Here's the gist of it. The way channeling works in the PWverse, as explained in case 2 of game 2 - at least for the Feys - is that the medium actually physically changes into the person being summoned; she has their voice and their thoughts, and the medium herself usually doesn't know what happened while she was "gone".

The "channeling" that happened in Edgeworth's M-U thread didn't happen like that. There was a connection made to the spirit world, but drug-induced, rather than anything that could've been taught through training.

Edgeworth himself saw and conversed with his dad's spirit, but the connection didn't manifest physically. He's not sure himself if the doctors could actually hear both sides of the conversation, and so he doesn't know if he told them anything they could use against himself or any of the other patients.

He does realize that he could have died during the procedure, and that scares him. There are two permament aftereffects of what happened. One is psychological trauma, which he hasn't dealt with yet. The other is that the connection re-establishes itself occasionally. Not clearly, and it's never been more than a murmur. It happens at times of high stress.

It's not something he can control; he couldn't go into a trance at this point or anything. It's more of a reminder than it is any actual ability, and something he doesn't want the world to know about.