Found: YA Fantasy About (Pre?)Teens in Alternate Dimension

I don’t remember too much about how the plot goes, but it opens with one of the main characters being hunted by a mechanical creature that kills you by rapidly aging you (I think it might have been called a Ticker?) while he was trying to get food. Later on, one of the girls was killed by a monster and shortly after a tame mechanical feline of some kind shows up, which is commented on by one of the characters as reminding them of said dead character (or something along those lines.) Book ends with one of the children escaping.

Extra details:

*Train tickets were used to get to and from the dimension. I don’t think there was anything off about the train?? Just the tickets.

*The book had a comic-style cover, with short comic segments akin to a light novel, but with a more western art style iirc

IT’S BEEN SOLVED BY A FRIEND—
for anyone curious the book is called Malice!!

Touchstone: Malice by Chris Wooding.