He was listening to music
So I press G and click the enemy 
in front of my 
once, then tell him I'm on the way. As I get closer, I ping 3 times the omw ping.
Once to show that I'm crossing river to go completely behind him, then two more times directly behind him. As 
I use my EQRW combo on between his 3 turrets next to the caster minions, while Zed finishes off the siege minions. I don't know the exact distance that caster minions are from siege minions, but it's pretty safe to say that if you're fighting siege minions, you can see everything happening by the caster minions.
Keep in mind I've ganked mid twice before now, using the same pings each time. Both times I got Zed a kill.
Anyways, I drop Heimer to roughly 50 health then I flash away because his mega turret is massaging my face, but it was too late and the mega turret kills me. Then Zed uses his ult to finish off Heimer. Yes, his ult [slayer-jinx-unamused]
At this point I ask, "WTF were you fucking doing Zed?"
You were listening to music so you didn't hear the pings, but how did you not see them? http://img11.deviantart.net/d752/i/2013/209/2/f/muay_thai_lee_sin_wallpaper_by_wacalac-d6fj1lj.jpg
None the less, he played an awesome game. I honored him after. We won easily, but his response confused me so I thought I'd share this situation, hoping somebody can bring some clarity to this.
Just for the hell of it, this is the distance between caster and siege minions http://lol.esportspedia.com/w/images/thumb/0/0b/MinionsFighting.png/259px-MinionsFighting.png
