Hunter Zolomon was a failed FBI agent who became a profiler for the Central City PD in the DC universe. He profiled the Rogues, which is the name given to the collection of Flash's enemies. He had a whole bunch of crap happen to him in his life: father killed his mother then was shot by cops, wife left him when he was kicked out of the FBI. A few months ago (in the Flash timeline) he was paralyzed from the waist down by Gorilla Grodd. He pleaded with the Flash to use the Cosmic Treadmill to travel back in time to change the past. Flash refused him, whichlead Hunter to hotwire to treadmill so he could do it himself. An explosion resulted in the destruction of the Flash museum and Hunter being bumped into another timeline that moves faster than our own. He decided to call himself Zoom, since he was now a speedster who hated the Flash. These are the basic points in his bio. His powers are basicall that since he is a faster than normal timeline, he can move at super speeds relative to our own timeline. He has no access to the speedforce, which is the source of the Flash's powers, and therefore can't do all the cool speedster stuff tht Flash can do. His power however made him much faster than the Flash. The Flash seemed to be traveling at normal speeds compared to Zoom, that's how fast he was. A side effect of this hyper-timeline is that "time windows" were opening up as well, windows to past events in Hunter's life. This is how he was defeated, he was stuck in one time window reliving the most terrible mistake in his life. He is in suspended animation in the supervillian prison in Central City whose name escapes me right now.
Namor is in no way fast enough for Zoom. He will have rely on reacting to Zoom's attacks, which are nothing to the near invulnerable Namor. So here we have the classic superstrength vs. superspeed battle. Namor could try to trap Zoom by collapsing the school on top of him, but Zoom is so fast that the falling debris wouldn't even be moving in his frame of reference. Namor isn't smart enough to realize what the time windows are or how to use them, so Zoom's apparent weakness goes unexploited. Namor's weakness is that he gets weaker the long he is away from water. Another problem that Namor has is that he becomes increasingly unstable or insane as his time away from water gets longer. I am not sure how weak he gets, meaning that I am not sure if he becomes so weak that Zoom could stab him. He definitely would become unconscious, which counts as a win for Zoom. I am not sure if there is some time limited on Zoom's connection to this timeline or some kind of danger point for his existence. I seem to remember that Jay Garrick, the first Flash and also the one to discover Zoom's powers, saying something about this but it wasn't explored. Zoom would seem to get tired since he only spends seconds at a time when he connects with this timeline, so he can last long enough to wait for Namor to fall.
Winner: Zoom II (Flash)