A woman in her 50s was rushed to the Heart Institute on Thursday morning after suffering a heart attack at City Hall.
According to paramedics, the woman collapsed on the floor of a first floor bathroom around 9:26 a.m.
Security staff went into action, grabbing a portable defibrillator and doing CPR until paramedics arrived.
They were able to restart her heart and get breathing on the way to the hospital.
She is listed in critical condition and expected to get an angioplasty.