Merlin stilled at Zach's musings, shrugging with a shoulder because even he was self aware enough to know that was exactly what he did - his overanalysis made him translate the signs he saw with a little more ease, made the symbols that cropped up everywhere match up into a big picture in a way that he wouldn't have held onto had he not been quite so anally retentive, but it had that backlash too.
But then, better to be safe than sorry, even though he never felt safe and always felt guilty. "I know." he said unapologetically. "But that's just who I am." Sure he tried not to let it get to silly levels but it was difficult to stop overthinking when you didn't know what was past, present or future and weren't sure if the world around you was a dream or reality; the visions weren't always as cryptic as the one that had started this mess.