I was the guy that got off and walked his bike through that patch.
However, after going through a couple of small wet/icy spots, I hit my brakes as I approached a curb that I have to pop to get around som train tracks and.... nothing..... at first, then the brake kicked in after the ice came off. Scary stuff.
I found out my usual riding partner left ahead of me (I was running a bit late), but then I passed him (we took different routes). I know I passed him because he saw my footprints where I went around the icy patch on the MUP.
Warm up already....!