The point of it is that it would take you into the inner section of the fort. Right now if you siege someone else you will have to fight in a second scene inside the halls and rooms of the main fort building if any enemies routed.
No, being hit by an arrow makes a different sound, more like a thud than a slash. Also you can see no arrowhead. Also you can pause at the killfeed to see the player that killed me had a horse icon, indicating it was a horse riding class.