How should I have handled this situation where I walked a young woman through a deserted and unlit part of my building without thinking it through.

I work in a large office and factory building, with many areas that aren’t currently used. I like exploring the building, so I’ve wandered through a lot of the areas. The other day I was visiting a client in the building and I encountered a young woman wandering the halls. I stop and asked who she was looking for, as she was obviously lost. She said she was looking for someone I didn’t know, but I figured it was one of the offices on the other side of the building. I took her in that direction, right into a deserted and unlit part of the building. It hit me in seconds how bad I screwed up, but I didn’t have a clue what to do then, so I just kept up a stream of conversation and let her trail behind me. We got to the right place and she thanked me several times. How should I have handled this after I realized I put her in a bad situation. And I’m at least twice her size.