"Your turn, Jim."
"Yeah Jim, go!"
After about an hour of orchestrating time-killing games in the Dunder Mifflin parking lot, Jim Halpert realizes everyone's expecting him to play, too. It's his turn to answer "Who Would You Do?" and while he fights to keep his expression blank, his brain is so clearly saying, "Pam."
But it's weird, because the last thing Jim wants is to "do" the receptionist—his best friend. "Doing" implies that he'd want to use her, or take something she owns without asking. Sandra Bullock, her he would've done if you'd asked him to play this game in high school—thanks to crass, lust-driven fantasies that were anything but probable. Sure, it's a matter of semantics, but this kind of thing matters to Jim. Pam matters.
What he does want is to hide with her somewhere, far away from the cameras, and let her do anything she's always been too scared or too embarrassed to do with Roy. He wants to hold all of Pam in his arms and let her know that she's wanted. And afterwards, he wants to run his fingers through her hair while she nestles into the crook of his arm and rests her head on his chest.
But no way in hell is he saying all that to a parking lot full of his coworkers, so he plays it off and answers "Kevin."