I have laminate floors and theirs one spot that when walked on the floor pushes down. There's a dip in the concrete. How can this be fixed?

Sounds like it should have been shimmed during install. Is this a floating floor?

If it is a floating floor, then its just a matter of pulling the planks apart and floating the floor with quick crete or floor leveler the resetting the planks. Bothersome but not complicated..
If it is glue down floor it can still be done but more complicated. Don't know all the circumstances but I hope this helps

Can you drill a pin hole in the laminate floor, and then maybe squirt some kind of glue or filler to reduce the flex in the floor?

The best fix is to pull it up and repair the dip and then put the floor back. I really don't see drilling a hole in the floor as a good idea. A hole small enough to not be obvious would probably not allow a material strong enough to do what you want to pass through very well. If I've missed anything post back and let me know GOOD LUCK, AC