I am in the exact same position as you! They gave me 24 hrs to accept or decline my offer. However, I am still waiting on other hospitals as well (Harris County being one of them) . Did you get an answer about accepting the offer and possibly rejecting it later ?
I applied to Memorial Hermann Saturday and got my rejection email Sunday. It does not specify why, but I am thinking it might be due to my low GPA. Has anyone with a 2.9 GPA or below got any interviews anywhere? I am loosing hope 😞