Once again not an avionics bay, it is # 3 air con pack bay. No access to it in flight. Only two ways in to that bay, # 1 thru the door which we have all seen in the pictures, you would need someone to help with this as there is no way off closing or opening the door from the inside & with out a bit of info the door is not a straight forward latch to open from the outside. # 2 very small access hole via the nose gear wheel well will allow you to enter the air on bays but you have to be a really slim person to get thru there. Blood stains on an aircraft are not unusual, bird strikes all the time, the amount of blood on landing in HRE was extremely unusual wouldn't you put gloves on.