In Black Fang's Dungeon, I explored and found Black Fang wig Seoni. Got the explore or evade option. But I can't figure out how to evade usIng the user interface. Help?

Yeah, this is confusing. The application asks you to encounter or evade even when evade isn't an option. Not sure why it does that.

 

Seoni won't be able to evade Black Fang unless she has a spell like Invisibility or Enfeeble in her hand.

You can always discard 2 cards (unless you have less than 2) to move to the Temple during the scenario.  Hit the thing beside your location text that looks like the Temple location.

In Black Fang's Dungeon, I explored and found Black Fang wig Seoni. Got the explore or evade option. But I can't figure out how to evade usIng the user interface. Help?

Sorry this needs to be communicated more clearly.

 

There is a location card in play called the Temple, which has a power:

When  you move here, discard a card. Any character at another location may evade an encounter and move here, discarding 2 cards instead of 1, then reset her hand and end her turn.

 

So what you are seeing is the option to trigger this location power. There should be a small icon showing the picture of the temple to the right of the location panel.