It's a puzzle

Today's observation has beaten even the person doing their suduku. I got off the train at Bank - the second busiest London Underground station and there in front of me, casually walking along, was a man doing a Rubik's cube puzzle!  He was doing quite well and I only saw him bump into the wall twice before I lost sight of him in the crowd. I wonder how many bruises he got before he either put the puzzle away or completed it? Unfortunately I think he managed to miss walking into any other passengers