This has recently come up at the table (I'm new to Free League games in general) and there is a mild question about how the rules are intended to work:
Panic Table Results timing: This is split along two lines of thought, one party believes that "next action" means just that, the PC's next action, not the current action. This would mean that only Panic Table Results 9*, 13, 14, and 15 would interfere with your current action (the one you are possibly triggering a Panic test from rolling).
* It's possible the GM might rule you fumble the item you're using for the action, but that could be a construed as an "EXPLETIVE" move, especially if the PC has a pile of Successes... (The "and the Successes I rolled don't matter?" question is rather what is prompting this question, as that seems counter-intuitive.)
[EDIT]
Okay, found the "If you roll a 10 or higher on your Panic Roll" rule, so apparently discarding a successful action is the intention. Now it's just a "expletive" move on "Drop Item". Hmmm.
[/EDIT]
Panic Table Result replacement: Several results 'seem' to last until the Panic ends with no clear end† for the result. However one party believes that the wording of "replaces a previous one" from: "If you are suffering from a panic effect (7+ on the Panic Roll) and are forced to make another Panic Roll, the new panic effect replaces the previous one" means just that, the new effect completely replaces the previous effect, thus a Character suffering from Trembling who later makes another Panic Test would lose the -2 penalty as Tremble (result 8) is replaced with Drop Item (result 9) at the minimum, other results if rolled worse.
† Primarily 8, 13, and 15, they seem to be implied as lasting until either 1 Turn passes, another PC makes a Command to relieve the Panic, or the PC is Broken. "No clear end" actually means, defintely lasts longer than 1 Round and potentially longer than combat. Result 11 can last as long as it takes to find a "safe" place... which could not be a possible thing to find.‡
‡ Yes, we get "and this is what GMs are for", however understanding the intent of the designers helps to inform rulings at the table. And yes, I get that the designers might not actually post on these forums, in which case I'm requesting other GM's input.