Glyph of Oreld and the Meaning of "Random"

[Elginb]

From the SOTM rule book:

"Glyph of Oreld (Intercept Order)
When one of your figures stops here, roll the 20-sided die. If you roll a 1 - 9, nothing happens. If your roll a 10 - 20, you may remove one random Order Marker from an opponent's Army Card."

When my friend and I were playing, we got into an argument about what "random" meant when I landed on the Glyph of Oreld. To me, it just meant that I could pick any Order Marker from my opponents' card so long as I didn't know what number order marker it was. My friend, however, said that it can hardly count as random, since you may be choosing based on which card the order marker is on. So he wanted to institute some way of making it purely random by rolling the 20-sider to determine which of the order markers I removed. To me, this seemed convoluted-- if they intended it to be so involved, they would have included more specific directions on how to pick a turn marker randomly.

Still, he makes a point-- it's not as random as, say, drawing straws.

You don't run into this ambiguity with similar powers with the Silver Surfer or Dund. With the Silver Surfer, you only choose from one army card, so you can't guess where the player might have put things (and I guess the opponent could shuffle the markers on that card to make it as random as possible). With Dund, you remove all order markers, so no ambiguity there.

If, in this case, they had used the wording "If you roll 10-20, choose one of your opponent's army cards. You may remove one random order marker from that army card", then there would be no ambiguity at all.

Anyway, anybody else run into this problem? If so, how do you see it? And what logic do you use to justify your interpretation?