2.5h is tight considering that you need to pass immigration twice, which is a hassle. And of course other miscellaneous things, like secondary security for passengers travelling to the US, check-in closed 1h before departure, etc.

If you intend to do so, make up some reasonable excuses why you will stay in China for 0 day(s), as it might be asked by the immigration official.

I personally do not recommend taking any risk and re-routing.