Garrus

Then, for Garrus red, shouldn't moving 0 fulfill the "if you do" step? And what should I check in the channel?

The extended discussion on this very subject

Can you discard a card to defend even if you don't have enough defense value to survive the attack?

Yes, you can discard and die.

Is Trailblazer's ability "You and friendly heroes in radius may ignore obstacles while performing movement actions" evaluated anew with every single move, or only at the start of the move action?

Movement isn't broken into 1-hex steps. Each instance of movement is a single step from starting space to the destination.

Garrus's Tier III Alt red says *"Target a unit adjacent to you. After the attack: You may move up to 2 spaces to a space adjacent to an enemy hero; if you do, push that hero 3 spaces, ignoring obstacles."* Does "after the attack" part targets an enemy hero before or after movement? Can you move to a space adjacent only to an immune enemy hero? The wording here is similar to Cutter's Primary Green.

You cannot. Check page 10.