Ferrari had no way of knowing if the old wheel/tyre was still attached properly or not, so couldn't risk sending Kimi out to do a lap to come back around to the pits, and they had slightly more important things to deal with at the time, than running down the pitlane to drag Kimi's car back and completing the pit-stop for him. Looking after Francesco was their priority, and by the time they were able to move him safely, Kimi's race was well and truly over (Can you imagine the outrage that would have been caused if they had simply dragged Francesco out the way, risking irreparable damage to his already broken leg, just to complete Kimi's pitstop?). For Kimi, he was told to stop the car immediately, which he did, and then he sat there waiting for the mechanics to drag him back (reversing in the pit lane is a complete no-no under rule 28.3: "At no time may a car be reversed in the pit lane under its own power." ), not realising that all of the mechanics were pre-occupied with their injured colleague. Chances are, Kimi felt Ferrari had screwed him over yet again, and so not knowing what had really happened, but realising his race was over, had a bit of a strop at the time and ditched the car where it was, for the mechanics to deal with and fetch it back, because he was done for the day.