Because I was forced to.
The gentle readers have a nasty habit of browbeating the poor writers until they cave and write that darn sequel that they never planned.

A Future Not Now was only meant to be a short story which was intended to examin how two (out of four) characters would initially cope with a particularly life altering situation. The monster that was spawned later is all the fault of the gentle readers 'encouragement' to write MORE!

Tank (who was too lazy to purposly plan sequels)