There's also the issue of timing. Realistically (that is, taking his speed into account) Mifune would be long done with the second leap by the time Herriman reappeared half a second after phasing out. Let's say Mifune can travel at least 500 mph, as I did earlier when trying to work out just how fast he'd have to move to appear invisible to a human eye. If that's the case, he could travel over 350 feet in the time it took Herriman to phase back in. That would put Herriman in front of Mifune and facing away when he re-appears. 

I also have a question. Can Herriman still see when he's in this nonexistent phase state? If so, how?