That would be my guess as well.

Either that or the Buy on Board items were running low so they added another cart or two of $3 stax chips, 3 musketeers and big cookies.

Seems like too fast a turnaround to offload a problem passenger but about right to unload a medical emergency, so that might have been it as well.

Maybe a concierge key passenger requested a stop at LAX so they could have a morning 763 ORD-LAX (didn't want to wait for the 3:10pm flt 93)?