Translation help

Hello everyone.

I'm playing a computer game and stumbled upon the following text I have trouble translating:

雰囲気の伝播速度ときたら驚異的である。
さきほどまで、ばらばらなことをしていた人々が、一糸 乱れず全く同じタイミングで、大笑いしたり、あるいは 、しんと静まりかえって悲しい顔をしたりする。

The expression that puzzles me the most is ばらばらなことをしていた人々. I don't know what this means.

My most wild guess would be (give or take a liberties that people not familiar with the game may find strange):

"The quickness in which (he) can perceive the atmosphere is astounding.
Ever since some time ago, he's able to place which people will react to the same input with either a joyful laugh or a dead silence."

雰囲気の伝播速度ときたら驚異的である。
[さきほどまで、ばらばらなことをしていた人々]が、一糸 乱れず全く同じタイミングで、大笑いしたり、あるいは 、しんと静まりかえって悲しい顔をしたりする。


- The quickness with which the atmosphere/mood spreads is astounding.
[People who were doing their own/varied things just until a while ago] (all of a sudden) at the exact same timing laugh out loud, or suddenly fall quiet and look sad.

I put brackets around the subject of the sentence, which means "people who were doing varied things/separate things until a while ago." "barabara na koto" means "separate things" or "varied things."

一糸乱れず is a description when something/someone moves in complete unison. So in this case I put it as "exactly" (at the same timing).

AK, out of pure curiosity, you are Japanese, but do you have American/English roots by any chance? I don't really know other Japanese people but you (except for other Japanese people who help out on this forum) who speak English so well.