To discover the cause of the accident, you need to send Wayne De Spiritwhistle and Patrick Bannon through the rooms in the 1st segment in a specific order.
First you send them to The Sound Stage (button with the megaphone)
Next you send the duo over to The Prop Store (button with the dumbbell)
Lastly you send the two to The Costume Room (button with the hanger)
After doing this, you will get the achievement by the first break.
Note that this is the path I took. Judging by the end screen, the only thing that matters might be the last step.