Scifi short story about janitorial work and interdimensional travel

[buttonsbeadslace]

Google has failed me, so I'm turning to you guys :) I first read this story a few years ago, online. I thought it was in Strange Horizons but maybe not? It's about a research facility where some sort of experimentation with space and time causes a certain hallway in the facility to fill up with mud and gore at regular intervals. It's told from the point of view of the woman hired to clean the hallway. She has an advanced degree and could get a job doing something more glamorous, but they pay her a lot because she's the only person they trust to go in that hallway and not mess with any Things Humankind Was Not Meant To Understand that she might see there.