Vertical Run — Joseph R. Garber

You think YOU had a killer workday. . .

Each morning in his 45th floor executive office, David Elliot savors the quiet
moments until the workday begins.

Until today, when his boss walks in and aims a gun at him.

For the rest of the day, he will be trapped in his midtown office building, and everyone David Elliot meets will try to kill him.

He has 24 hours to find out why. . .