None of them were really anything amazing.
One of the videaos of the flashing light appears to be a just flashing light. It can be seen when it is not flashing too, which makes it appear that
it is a physical object that was placed there.
The flashing light that you saw in one of those videos was the EMF detector. Supposedly it is used to detect 'paranormal' things in the vacinity.
That is why the one guy is counting. You can hear him say "10" and then count. That thing was placed there, that is the detector, and the light
flashes when it detects something. I have seen those used before in other shows and the like on TV...very good site though.