What happens if I abandon a terror mission?

Playing ironman at the moment. I am doing an enemy within terror mission where you have to press a button on a cargo boat and then evacuate your soldiers. Things went southside, I cant get to the button, just gotta get out. If I were to leave, does the terror mission count as a loss or can i retry after I evacuate?

Is that a terror mission? I know that mission involves just a complete mess of Chryssalids but I thought it was a Council Mission.

That's a Council mission. It's a Site Recon, the only one of its kind as far as I know. I think you've got one shot at it, successful or not.

After trying it once with a woefully unprepared squad and getting all but one soldier killed I've just ignored it on subsequent playthroughs. Its only ever been offered once per game, and nothing negative has happened due to skipping it.

@tjk: If that was, in fact, a terror mission, abandoning a terror mission allows your soldiers to live, but counts as failing which, as you know, means the country it took place in will immediately leave the council.