Stuck in Final Offer

[PhantomTa2]

I've defeated Deathstroke and don't know the way out, so I accidentally went back towards the beginning of the level thinking that was the way out but most of the doors seem to be locked. I tried going back to the arena and the part where you go through the vent (in the Casino), use the cryptopgraph-thingymabob, open the door and three guys come out (2 armed 1 unarmed), that door just says inaccessible and I have no way of getting out of the ship. I've been running around for about 45 minutes now trying to find a way out.
There's not even a stage/level select so I can't go back to just after, or before, beating Deathstroke, instead, if I've made a game-breaking mistake, I have to start the game again.
If anyone could help me it would be greatly appreciated.

Thank you for your time

PhantomTa2

[FableForager]

You should go away from the ship by the way you come there.

[PhantomTa2]

I know, but I can't find the way out, that's what I'm saying

[PhantomTa2]

The exit doors seem to be locked and I can't get back to the arena

[Realzameer]

http://ca.ign.com/wikis/batman-arkham-origins/Murder_Mystery?objectid=165718 (Brief IGN Article segment)
http://www.youtube.com/watch?v=v36JnLySEGc&t=81m20s (Specific video I found without commentary, if the time signature doesn't work it's at 1:21:20)

I'd suggest taking a look at the Youtube link, it goes right after the Deathstroke segment in the Arena area. I hope this helps!

Edit: http://steamcommunity.com/app/209000/discussions/0/666824800900538769/ is another Steam discussion on the same topic, if all else fails try checking that. I saw someone in another discussion say that the door unlocks after the Penguin video plays (if you haven't seen that yet), which will show up when you attempt to open the locked door above the arena.

[PhantomTa2]

Thanks for the reply, but I can't get back to the arena

[PhantomTa2]

Never mind, got p***ed off with it and deleted the profile

[Ronin]

This is a valid point, but definitely not a bug. This happens when you ended up going north instead of south after defeating DeathStroke. You can get back to the Boiler Room by going all the way down to Deck 3. It's the platform at the same level as the water. There's a wall that can be destroyed with the Explosive Gel (you may have already destroyed it earlier). Enter the passage. Instead of crawling under the prominent opening in front of you, look all the way up. You should see R1 flash on your screen that says you can use the Batclaw. It's a vent that allows you to go through the Deck Access Corridor, and ultimately leads to the Boiler Room. Once in the said room, everything is straightforward - continue heading south until you get to the exit.

For a detailed explanation, check this link http://www.ronixus.com/2014/01/batman-arkham-origins-stuck-final-offer.html

[PhantomTa2]

Yeah, figured it out lol. You'd have thought it would have been blocked off for that part, really

[Ronin]

This almost made me start over too. But I knew it's not possible that the developers missed it and not even issued a patch, so I kept trying until I found the way out.