I don't quite get the path Felzhen is supposed to take. F1 is his starting position at the beginning of round 1, right? F2 and F3 are his positions at the end of rounds 2 and 3 respectively, if I understand the description right. So where is he at the end of round 1?
Also, what does he do once he reaches F3? The text says he examines the device, but he surely doesn't just keeps doing that until the PCs reach him. At the same time, it would be kind of silly if he instantly escapes on round 4 or 5 be going around another corner, since there is no reason the PCs would be unable to follow him other than the end of the map.