A Balrog is Come! but fled the siege

[Henry]

Nazugls can enter and leave a shadow fortress under siege at will.
What about the Balrog if he has a movement of 2 because the the "A Balrogis Come" card? Can he escape the siege or reenter?

[Veldrin]

Very Good Question!

I have emailed Roberto (the designer) to get an official answer.

This might come down to the question: Do Balrogs have wings?

If you ask me he cannot do so (based on the theme), see here for my reasoning behind Balrogs not having wings: www.glyphweb.com/arda/b/balrogs.html

[Veldrin]

Roberto (the designer) answered that the Balrog should follow the same movment rules as the Mouth of Sauron, so no entering besieged Strongholds.