This was an unusual dream which was not a lucid dream but had two strange points and a surprising reference to another dream which I had few years ago.

First, a brief overview of the dream I had few years ago AFAIR:

I was in a big city, working in a job related to computers. I was given an unusual task: I was to meet with another young guy who was working in his apparement in a big block on some secret, advanced project.
But when I got there, it appeared that the thing that he was working on had something to do with conspiracy, and I was shocked when I went inside his home. The project's results told something about the people at power, particularly the secret advanced technology at their hands (which masses had no idea about).
It wasn't long when - while looking at the monitor inside his spacy room - we directly faced this advanced technology suddenly outside of the window... These people at power somehow found out about us, and sent a flying, tech-edge vehicle which hung behind the glass window, and shined with a huge blinding light.
He warned me to escape from there, and when we did, the apparment has been destroyed in seconds by this light - it worked a bit like a bomb, but apparently could be controlled and the explosion was limited to that one appartement in this sky-craper building.
Soon the whole city plunged into chaos, while we were hiding and running through its streets...

Now the today's deam:
I was walking through an area of high blocks, and was about to leave it, when I noticed 2 other blocks hidden previously (behind the other ones) and for no reason got curious about them. So I went into that area, and strangely I felt like I was on a private property. There were almost no people, just 2 young women, looking at me from a distance, but despite a feeling of pressure to leave, they behaved quite friendly.

Then I recalled that one of the blocks - on the left - was the one that I was inside in the other dream (the one I described above)! I decided to enter it, got to the appartement without even knocking. Inside was that same guy which I mentioned above: he seemingly still had the same job. He wasn't angry that I came in like without invitation or even knocking. I asked him to show me the same thing on his computer that we didn't have time previously for, and he agreed.

When looking at the monitor, I was flooded with a very strong blinding light coming from the computer, like the monitor itself was a bridge to another non-physical dimension! I couldn't see anything and I had to close my eyes, the light was so strong. It felt almost physically painful. I didn't remember much, therefore, what was it about. Then I thought, in the dreaem, that I need to try such thing (exposition to this show/light) beyond the dream next time so that I was better able to handle this.

He seemed to be relaxed and didn't bother. I was about to leave, hoping that we would get in a closer touch soon...