I need help on a medical question please help?

My friends son got a laceration to the liver, the doctor who looked at him stated it happen at 10 pm, but here where it gets tricky. My friend and the doctor noticed it at 8:45 pm, but the medical doctor said it happen later? how could that happen if we see bruises on his stomoach. My friend doesnt not know when it happen. He son is only 18 months and he can not talk, my question , when do you think it happen? could it happen the day before or on that same day? please help thanks and god bless