With Rama on board, you've now got a number of reasons to return the Ark. One of them is the Wreck Room, a Danger Room style trainer you can fight in for loot and other rewards.
Even your relatively low level squad is sharp enough to clear the first few levels easily, and good tactics can help you clear some higher ones (or you can return once you've levelled a bit. Hardtack can be a strong choice here- his harpoon lets you separate the enemy team into bite-sized chunks, so as long as you're canny about cover during the cool-down period, you can take apart most waves one by one.
Once you've investigated the Wreck Room, you'll get an objective for a mission briefing back in ops. You'll learn a lot about enemy asset Hammersmith, and unlock a slew of new missions, most of them dealing with agent recruitment.
Now is a good time to expand your roster and explore the city a bit- the campaign will still be waiting when you get back.