I actually just played some of this for the first time. I'm confused, since scp-173 is normally just locked-up in a storage container. How is he clipping around the map? If you close the door behind you when you run out of the room, he should be stuck until the filth he generates achieves such pressure that it breaks the door. That said, it's hard to know much about scp-173, since there's a complete ban on altering the entry to make it better or more informative. As someone points out in the comments, there's no need for anyone to ever look at 173 if all they're doing is containing it; you could easily construct a system that would automatically clean the room without the need to risk a breach.
It also occurs to me how much trouble this site is in if it actually lost power. Thinking of this scp without the ban on changes, it probably has similar measures to other visually-cued scps, ie triple backed-up circuits and generators everywhere.
There's another scp that operates on a similar principle that actually will teleport to everyone who's seen it and kill them, but I can't remember the number. IIRC, it was a little statue that would teleport on top of their corpse.
Edit: spoilers go all yucky and have a new-line character with them