The 救急車 was fast getting there when they heard who it was for. BONES（ボーンズ）-骨は語る- was famous, nobody wanted her dying, expect for the crimanls that she put in jail. Booth was to worried about her to stay at the crime scene, to make sure that everything was bagged and tagged.
He rode the 救急車 back to the hospital with her, Booth was going to be there when she wakes up, he don't want her being alone. Ever again. The doctors had talked to Booth about her health, she was in good shape, and young, so she wouldn't have any damage. It would just take some time for her to wake up where she hit her head....