Can you even do it?

I'm unsure since you cannot satisfy the "reduce your agility" portion of the card. Has this been FAQ'd?

Yes, you can use Expose. It will reduce your agility to "0" because that's the absolute minumum.

Could be worth it, if you've got a Gunner and/or another action every turn.

I should point out that Range 3 and Asteroid bonuses are not increases to Agility. So if you Expose on a Decimator, you will still get both if applicable.