It's time to finish some of the subquests. Proceed directly to section C, because you won't perform any new activities in sections A and B. Talk to The Nurse and he'll thank you for delivering the poison. The Nurse will reward you with a cigarette pack (32 - Cryo Inmate) [#154]. You can also ask him to loan you the money, but only if you have less than 10 credits. Be careful, though. If you don't pay him back you'll have to defeat his goons at some point of the game!
You should also talk to Gulag while you're here. Give him back the red tube [#155] and he'll rewarded you with a... cigarette pack (3 - Narc Land)! What a surprise! ;-) Finally go to section D. Find Twotongue and give him the injector. One more cigarette pack (55 - Billy Bob) will be added to your inventory.
Twotongue will now have a new assignment for you - collecting moths. Look around this section and you'll find a lot of moths flying around. Wait for one of the moths to get closer and catch it by pressing the action key [#156]. Once you have the insect return to Twotongue and give him the moth. You'll now be given three options:
1) you can buy poison for 10 credits (useless)
2) you can buy drugs for 10 credits (buy those if you plan on posing as a drug addict to reach the mines and not by defeating Bam)
3) you can buy a cigarette pack for 10 moths
Obviously in order to get your hands on the cigarette pack you must begin collecting moths. Aside from the ones you've just caught, there are sixteen other moths in the Recreation Area. Most of the moths can be found in sections B and C [#157]. Try catching them all and then return to the dealer. Exchange 10 moths for a cigarette pack (22 -Basilica Interior Detail 9). Sadly, in order to get your hands on the final pack, you're going to need 20 moths. You can't find the sufficient number of them here, so we'll return to this quest later on. Head on to the passageway leading to Tower 17 Base.