Purdy had more time in the pocket to pick a receiver and make a throw than Mahomes did for the first quarter. The 49ers really came after Mahomes, keeping him in the pocket and not allowing him to get outside.
The 2nd half that changed, Purdy started getting pressure from Jones and the Chiefs started to blitz him, forcing him to get rid of the ball quicker than he would have wanted. Mahomes went the other way, the line did a better job allowing him more time, and the two runs he had, were set your foot, nothing there and take off right up the middle. Both times they caught SF in a man coverage, so their backs were turned as he broke containment and sprinted up the field. That 4th down run my Mahomes was textbook, they motioned right to left, Mahomes sprints to his right, had Kelsey in front of him and wide to pass too if he needed it, the LB goes with Kelsey and Mahomes flew up into the open gap for 7 easy yards on a 4th and 1. Just a great play call by the Chiefs.