Will confess to not having time to read the IC until later today, so am unclear on exactly what the problem is, but I'll clarify what I can.

[@Old Amsterdam]Mary doesn't need to cut through a shield, since it only covers her against Dragon. Mary will just sink the knife in Vegas's back. 

[@Banana] I'll try to explain. Capes who haven't done much are held much in the same way as criminals, but within the local PRT or Protectorate base. The exceptions to this rule are Strangers and some Masters who have specialised containment cells and protocols in place. If a cape is a multiple offender or commits mass murder or another particularly bad crime, they are sent to the Birdcage.

Which is a fully-automated, unmanned, maximum-security prison set inside of a pocket dimension inside a mountain, IIRC. Once you are in the Birdcage, you never leave.