'Leave him, he's mine!' came a barked command behind me. It was the Irishman with the saucer eyes, and there was an icy calm in his voice that made my heart lurch.

I jumped the coffee table, clipped it, and almost fell into the front door, grabbing at the handle and yanking it as hard as I could, only noticing at the last second that the chain was on. Incredibly, I didn't panic, just flicked the chain across in one movement, threw the door open and ran out into the corridor.

I felt something swish through the air behind me. The knife. It touched the material of my shirt but didn't break it. He was right behind me, just feet away. I could hear him breathing.

I started running, realizing as soon as I did so that I was going the wrong way from the lifts, and that the corridor ahead seemed to be a dead end. I yelled again, hoping someone would hear me, thinking that if I made enough noise my pursuer would panic and turn back; but there was nothing, just an intensely loud silence. It was like I was suddenly in the middle of a nightmare.

Behind me he kept coming, his breath almost on my neck, and it was his patient, predatory silence that terrified me the most.

There was a door at the end with a staircase sign above it, and I felt another surge of hope and accelerated, shouting as loudly as I could into the silence. I hit the door head on in a way that would have made Maxwell proud. Because it was a swing door, it flew open and I stumbled, almost losing my footing before swinging hard right and charging down the staircase, taking the steps three at a time, knowing that if I fell I was dead, no question.

Every part of me seemed to ache from the exertion of running, and in my semi-inebriated state I wasn't sure how long I could keep it up for. I could still hear him, ever so close, and I had a desperate urge to look round, but knew it might cost me a precious quarter second which might end up being the difference between life and death. Instead, I started taking the steps four at a time, praying that the doorman was at his desk so at least he might be able to help. Praying that I made it that far.