I can remember that day as if it were yesterday. The image of it burns on my closed eyelids when I blink, when I sleep. I had boarded the underground train, the 311, at King’s Cross Street Pancras and had managed to squeeze into a seat on the already bustling train, even though it was only ten to nine in the morning. Only after the train’s doors had beeped and closed tight shut and the train ground into motion that it happened, all at once.

Screams. That’s nearly all I can remember. Shrieking, high-pitched screams, ripping through the heavy underground air like a sharp blade, piercing my eardrums and sending violent tremors down my spine. Then, the longest second of my life. Complete silence. No movement. I could hear my own heart beating hard against my chest, a drum beat steadily building in pace until a dull thud, and my head was ripped open by the noise.

The door of the carriage to my left blew outwards, flying down mine, the solid iron frame missing my face by inches. Glass blasted everywhere, bouncing off the underground tunnel walls and rebounding into the cabin like bullets, stabbing my skin and forcing me to throw my hands wildly over my head as I bumped out of my seat and fell flat against the cold metal floor of the train.

Blood that was not my own splattered into my face and eyes and I wanted, but couldn’t spit out as a blazing inferno tore the carriages apart. Suddenly I was sliding down towards the open door as the left hand side of the train hit the tracks, its wheels blown apart, sparks flying upwards like a glittering firework display. My hands flailed uncontrollably outwards, fumbling for anything to grab onto. I found someone’s leg. I opened my eyes fractionally, the thick dust straining my sight, but I could still see the blankness of the man’s eyes and let go instantly; disgusted, sickened and needing to throw up. My head clanged hard against a steel pole and I gripped it hard, the pain flooding through my brain mingled with the screeching of metal on metal, the train being dragged unceremoniously along the tunnel floor.

Then it was over. The train slowed and halted and the sudden motion jolted me from my position and I slid to the end of the carriage, my feet colliding with the metal wall. What had happened? Why, on my one day off this week, did this have to happen? My job is to save the lives of others, but now I am the helpless one.