ID on Bug found in house?

Alright, so I realize it's a long shot without a picture but I wanted to see if anyone had an idea on what bug this is based on the description.

Twice now, I've found the same bug in the bathroom that looks very similar to the German cockroach except it's about 2 inches long. I wish I could get a pic but it moves like lightening and both attempts to catch (or kill) failed. I know water bug is on the tips of everyone's tongues but it definitely was not a water bug. It looked different and was also reddish black. I've never heard of them getting that big (german cockroaches, not water beetles) and it was a single one in a bathroom which is the farthest room possible from the kitchen. I'm guessing it's some bug that wandered in from outside to escape the cold and is not (hopefully) a pest.

Any ideas on what it could be from the admittedly poor description?

My guesses:
Tile-horned Prionus (Prionus imbricornis)
Pole Borer (Parandra brunnea)
Ground Beetle (Harpalus caliginosus) or H. katiae
Stag Beetle (Lucanus capreolus)

Lepisma saccharina, frequently called silverfish, fishmoths, carpet sharks or paramites.

Credit goes to Wikipedia cuz I am not smart enough to puke all that scientific jargon.

Thanks for the responses! I googled imaged all of the pictures and I think the lepisma saccharina is closest but I'm not completely sold. I'm going to start treating the bathroom as if it is though just in case.

I wish it had been a stag beetle though, that's a very cool looking bug!

Let us know if you find out what it is.