Freaking raiders. I guess they wanted the highest possible seed
I listened to replays of some of the post game interviews. The Raiders coach said they had discussed whether just to take the tie during the final drive, which is part of why they were letting the clock run while handing off, but when the Chargers called time out with 20 or so seconds left, they went with the run again and the gain was enough to put them in field goal range (around 48 yards). The Chargers coach explained the time out by saying he wanted to get his run stopping defense in instead of the pass defense personnel he had been playing in the final drive. Said something to the effect of "we called for our best defense but they just beat us."
I can see strategically the right move for the Raiders being to make sure they were the last team to hold the ball. They are in either way. But once they got to field goal range, the fair sporting play is to try to kick like you would in a normal game and not play favorites between the LAC and Pitt. It did run the risk of a block & return, which I suppose is more likely than a fumbled kneel down and return.