Reach Adventure 2: The Calixcuel Incident (2e)
In The Calixcuel Incident¸ the Travellers are visiting an underwater city when a disaster causes it to begin leaking. Amid the chaos¸ they discover they have the means to save the entire city¸ if they can only reach and start the auxiliary reactor. However¸ the reactor is located in a secure bunker on the seabed¸ separate from the city¸ and between the Travellers and their destination are mobs of panicking citizens¸ jammed bulkhead hatches and several kilometres of ocean.
Not to mention the squid....
The Calixcuel Incident includes full rules for: