OK, so its been established that the healing doesn't work, but there is still the problem that the rules as written clearly define every creature as it own enemy.
Well, let's take your example and assume that PCs count as their own enemies. I think this is a somewhat crazy assertion, but you are making the arguments for it, so I guess it falls on you to support how it works in-game.
If it doesn't work in-game, then I'd think we're clearly looking at an infinite oregano-style interpretation.
(1) Rangers can never mark opponents, since they are their own enemy, and they are by definition closest to themselves.
(2) Swordmages always hurt themselves with Greenflame blade.
(3) As Hyp pointed out, you cannot move because you cannot end your movement in an enemy's space.
(4) Warlocks can never curse anyone, because they need to target the closest enemy. Again, by definition, that is them.
Are you proposing that all of these side-effects are, in fact, how 4e should be played? Without ever moving, and without any strikers ever using their targeting abilities?
-O