For such a short (and easily missed) Side Job, it’s somewhat surprising there’s any dialogue choices of note. Alas, it is possible to do most of what little work this quest demands and walk away without its main prize.
Play through the quest normally, follow Mitch’s instructions, and after sending Scorpion out with a bang, to talk to him. When he offers you a beer, respond with “Sure thing.” or “Nothing for me, thanks.”, then follow up with “Why’d you ask me to help?” and he’ll offer you one of Scorpion’s possessions. This just so happens to be a Scorpion Action Figure, which you can use to decorate your apartment. It’s not much, but it’s the most interesting reward this Side Job offers.
If you say “I gotta go.” when Mitch offers you a beer, you’ll void this Action Figure.