So my problem with Vampire Diaries 1.17 is the same problem I have with most vampire canons where you try to do these things.
I don't care if the undercover assailant in your break in story is human or vampire. If it makes noise, the vampires will hear it. This includes whispered fighting and planning and orders; walking on the floor boards and running up stairs; any and all conflict fighting wherein you stab someone or throw them into things; and, as always, your romantic and snarky reunion banter.
This is one of the details that is the fastest to frustrate me in the anyone's Vampire canon. If you are making any noise, the vampires hear you. If the vampires hear you, your caper-break-in-save-someone plot is over. If you want to me to suddenly believe for the sake of your episode that your army of vampires suddenly don't have sensitive hearing, don't give them supersensitive hearing in the first place.
This is why I did
neenie's Volterra Plot that way I did, with like three sentences in total.