I don't think Mesaana is willing to take an Oath and then try and revoke it. The Forsaken know that the Oaths are as binding as shackles, and it's the last thing that Mesaana needs if she suddenly needs to take flight. Not only that, but I think it's possible that she might die if she takes the Oaths... she's about as old as Cadsuane.

Mesaana therefore needs to appear to take the Oaths while surrounded by women who are more than willing to overwhelm and execute her. I cannot imagine that this is an easy thing to do, or Semirhage would have tried it in the AOL instead of running away and joining the Shadow.

Mesaana has to therefore rely on some form of third Age ignorance, much like hiding cards while playing poker and hoping that no one notices. There are some possibilities as other posters have noted. I on the other hand think that she'll use a flow of Spirit and take the Oaths normally, and then use a second reversed flow that touches another point on the ter'angreal and makes it useless. Much like Sammael knew the callbox in detail, it seems that all of them know ter'angreal down to their smallest degrees. While someone in the AOL would have watched her trying something like this, I think she could dupe the Tower Aes Sedai.