There was relief, fear and anger among passengers, including a woman who was nine months pregnant, as they told of explosions, smoke-filled carriages and stumbling along a dimly lit tunnel to escape their crippled train.
The first hint of what was to come happened about 9.15am, two minutes after the train had left Kam Sheung Road station. The explosion was followed by white smoke, a shower of debris and another bang.
Then the train stopped, the doors opened and passengers were asked to start walking along Tai Lam Tunnel away from the smoke.
Kitty Fong, who is nine months pregnant, was among those who had to make the 2km trek to the next station, Tsuen Wan West.
'It was tiring. I felt like throwing up. But all I could think about was leaving the scene as soon as possible,' said Mrs Fong, who needed hospital treatment. 'Luckily, I got help and comfort from a kind-hearted couple. They supported me to prevent me from stumbling in the dim tunnel.'
She was angry at the speed of response of West Rail staff.
'I saw the first staff coming to help only about 20 minutes after the incident. It could have been very dangerous if someone fell down or collapsed in the tunnel.'
Another woman said the situation was a mess. 'The driver asked us to run away from the smoke. But we were in the last carriage and we had nowhere to escape.
'It was chaotic. People were crying and screaming. Luckily, the carriage was not crowded and passengers quickly opened some windows.'
For Shue Yan University journalism student Leung Siu-kin, the explosion represented opportunity.
Though fellow passengers urged the 21-year-old to carry on to safety with them, he turned back halfway through the evacuation.
For the next two hours he lingered in the tunnel, taking more than 100 photos. The photos, posted on the website of the Shue Yan journalism department's publication Shuonline, were widely used by the city's media.
'People kept telling me to run away ... but I found it too good an opportunity to miss,' he said after an evening class.