Shelley Mitchell was a high-ranking worker at an inner-London office block. She spoke with a thick Scottish accent.
On the day Shelley, with her boss Terry and other employee Mike, were giving a presentation to Mr. Nagata for a merger between their company and Nagata Beer; an Anomaly to the Precambrian opened in the office block and released a thick, misty sulphuric gas throughout the building. When the fog was mistaken for a fire and triggered the fire alarms, Shelley, Terry and Mike ignored it to continue their presentation, even as the fog seeped through the halls outside their office. Eventually, Shelley admitted to noticing a smell, so they distracted Mr. Nagata with some video mockups whilst Terry went out to investigate. To Shelley and Mike's horror, they saw Terry horribly attacked and dragged off to his death in the fog, killed by the Precambrian Worms lurking in it.
Afterwards, Shelley and Mike were left huddling in the office corner as the fog gradually began to seep into their office. Eventually, Mr. Nagata resumed the communication to tell Shelley that he'd been convinced by the presentation and congratulated her; at which Shelley comically leaned out over the table into view to thank Mr. Nagata, before using her laptop to fend off a Worm that then tried to get into the office. Moments later, the Anomaly Research Centre team arrived, using leaf blowers to keep the fog back as they escorted Terry and Mike downstairs to safety. In the lobby, Shelley demanded to know from a speechless Nick Cutter what was going on, at which point Jenny Lewis resumed her PR duties, covering the fog up as smoke from the fire, and dismissing Shelley's talk about the creatures with the advice that she think about how the story would sound to others.