You can in the storyline get the RC car before you go through the dead city for the first time. If you do the sheriff's quests and get the the Cuprino, he'll give you the job to take out the Shrouded clan.
Yes . . . you are right, you can. . . but I didn't. And I now know that if you don't go back a 2nd time, prior to the data retrieval mission for Capt Marshall, the contents of the room will be changed in the data mission and the Large Mutant card will not be there. . .I had to go back to an old save, almost 3 hours back, which luckily I had, go to Dead City and fight a bunch of mutants, get a dozen or more of their bone pile rewards, and finally retrieving the collectors card from the room. Next I began playing catch up until I finally got to the Dead City mission again.
So . . . to all interested: If you don't get the Large Mutant card the first time you are in Dead City, you can only get it get it by returning there (make sure you have an RC Bomb car to send thru the drain tunnel) a 2nd time, and that time must be before getting the data retrieval mission from capt Marshall. Once you've done that you can continue on and get the data mission . . . which will therefore be your 3rd trip thru the Dead City.
I hope this helps some of you trying to get all of the collector cards because once you get the data mission to Dead City you are SOL if you think you are going to get the card during that mission and you won't be able to get it at all during your present play through the game.