A Horror Story in just 1 Sentence

3 friends lived in a flat on the 100th floor...
One day when the lift was not working they decided to tell each other stories as they walked up the stairs.
The 1st told a comic story till the 50th floor,
2nd told an action story till the 99th floor and
the 3rd told a horror story in just 1 sentence -

"I forgot the flat keys in the car."