I really don't want to get involved in this - But you have just proven my point there. It cannot be proven from the medical evidence. You have just acknowledged an element of doubtYou've just contradicted yourself here because a 'laceration' means tearing and bleeding. Now perhaps you're trying to argue 'something else could have caused it'. Which is very unlikely but could be true and we then have to see how likely that is given she is saying they raped her. FYI juries are supposed to go on likelyhood on events happening..
As for who do you blame - Its up to the prosecution to bring best evidence forward and fault lies with the medical doctor & PSNI regards this imo.