I think my answers during the playtests sort of took away some of the goodness of Panels. The main advantage of them that I see is that nobody gets left out no matter what is happening. If Kim's character is looking up something in a library while John's character is in a combat while Ryan's character is running from the bad guys, we don't skip Kim just because her character is not in an "action" scene.
Panels are the length of time it takes for something to happen. That is the measure of a Panel, and it's vagueness is why a Panel is a variable length of time. A conversation can be one Panel, or it can be many. A fight can be one Panel or many. A chase can be one Panel or many. The important thing is when something happens. For example:
"I call my contact, George the cabbie."That's one Panel. One thing has happened. The PC has asked George for help and George has agreed. The key is that we could boil down that conversation to one exchange between GM and player. Now, here's another example.
"He picks up. 'Dis is George! Da cabbie!'"
(teeth gritted because of the rule that you can't make fun of people trying to play someone with an accent) "Hey, George, it's me."
"Hey! What's happenin', chief?"
"George, I need some information. Information on Big Boy Thompson."
"Whoa, that Thompson's bad news. Whaddya need to know?"
"I need to know about his bank accounts. You think you can get a hold of a credit card receipt from him?"
"Sure t'ing! I'll call ya back when I get it!"
"Take care, George.' I hang up."
"I call my contact, George the cabbie."That's one Panel. One thing has happened. The PC has called George and George has warned him about the cartel.
"He picks up. 'Dis is George! Da cabbie!'"
(teeth gritted because of the rule that you can't make fun of people trying to play someone with an accent) "Hey, George, it's me."
"There's a pause. 'I shouldn't be talking to you, chief.'"
"Why not?"
"Word is that the cartel is after yas!"
"I'll be fine, George. Thanks for the tip. Now I need some information on Big Boy Thompson..." (And so on, in the same vein as in the first example.)That's another Panel. So this conversation has taken two Panels. One for George to warn the PC, and one for the PC to ask for information. Those are the two things that have happened.
Basically the import of this is that the same amount of things will happen to every character in the game, even if this temporarily takes them out of in-character synchronization. This means that you don't have to leap in and shout over people in order to be sure you get your character spotlight time. You're guaranteed it. You can voluntarily give up some of it if you want, but you are guaranteed one-fifth of the actions taken by the party in toto during the game.