Gunn, 28, a TV producer at HHCL/Red Cell, can't stand heights. Or at least she couldn't until touching ground again having ascended the side of a Manhattan skyscraper on a window cleaner's platform.
Job hunters will be pleased to know that ordeals such as this are not part of a tough new initiation rite at the WPP-owned agency. Quite the reverse.
In fact, Gunn won the chance to exorcise her personal demons in the agency's Dreamcatcher initiative, a quarterly competition that offers staff a thousand quid and a week off work to realise an unfulfilled ambition.
Not for her the vegetarian cookery course that took the winner of the previous Dreamcatcher competition to India. Nor the notion of joining a circus school, the stated ambition of one of the entrants forthe competition this time. (Who said they have got too many clowns and jugglers at HHCL/Red Cell already?)
Instead, Gunn found herself braving the elements 16 storeys above the traffic skirting the Hudson River. It was all done with the help of the expert high-rise squeegee man Brent Weingard, who came highly recommended by the International Window Cleaning Association (yes, there really is such a thing).
Gunn's verdict? "Although I was terrified when I was up there, I came down thinking 'I could do that again' and I really felt a sense of achievement," she said.
Sid McGath, the HHCL planning partner who dreamed up Dreamcatcher, says it's all about creating opportunities for people to bring fresh ideas, enthusiasm and vigour back to their jobs.
Meanwhile, if you've got a skyscraper that could do with a good leathering, you know where to go.