Concrete is a semiconductor and wet concrete is a pretty good conductor. See if you can light a 7-1/2W bulb that's hooked up between the hot line and the floor. If that works, try a 100W bulb.
Since you're not dead I guess the current flow, 120v through concrete resistance through skin resistance through body resistance and back through skin resistance was less than 20 mA or so. 10 mA is painful and 1 mA is a tingle.
I had one probe under a wire nut then the other one dropped to the floor and my meter started beeping. Maybe I will do some experimenting.
There was a guy in EC&M who got 120v and seemed OK but later developed problems. His expert witness said that the guy might have gotten 500 mA through his body.
This is 120v/0.5A = 240 ohms. Almost nobody almost none of the time who is not soaking wet has a resistance this low but I guess it can happen. 3000 ohms and up is more reasonable.