Rode across town to another location over lunch. I was riding through the oldest remaining section of the MUP that hasn't been updated, which means it's still at the original 7 foot width (versus 12 feet.) As I was riding along this section I saw a person walking coming towards me. Behind her was another guy on a bike also coming in my direction. I could tell that the three of us were going to converge at the same time. With the narrow width of the MUP there wasn't enough room to pass three wide (which I don't like to do even on a 12 foot section).

Because the rider coming towards me would have to move to his left into my "lane" to pass the pedestrian, the onus was on him to yield until it was safe to pass. I don't always assume that other riders are going to do this, but I saw him stop pedaling a ways behind the pedestrian and it looked like he was slowing so I held my pace.

Suddenly the guy slammed his feet to the ground attempting to stop Flintstone-style. At that point I realized that either he didn't know how to use his brakes, or they were completely non-functional. I couldn't move off the trail to my right because there was a steep drop off into the river with no railing. I was also too late to stop in time, so I slowed and moved to the right as much as I could.

The guy somehow managed to squeeze between the two of us, dragging his feet the whole time with a panicked look on his face as he was attempting to stop.

Idiot.