Cynthia Zarazir, who was elected to parliament in May polls, is the latest in a growing number of angry depositors who are forcing Lebanese lenders to unlock savings trapped under informal capital controls imposed amid an unprecedented financial crisis.
Zarazir entered her bank branch in a northern suburb of Beirut at around 9 a.m. (0600 GMT) to demand $8,500 to pay for surgery costs not covered by her health insurance, her lawyer Fouad Debs said from inside the bank.
"We will not leave until we get the money," Debs told AFP, nearly three hours after they entered the branch.
Zarazir said she had rejected an offer from the bank to withdraw an unlimited amount in Lebanese pounds at a rate of 8,000 pounds to the dollar - which would represent a roughly 80-percent haircut on the value of her funds.
Several activists gathered outside the bank to support Zarazir, whose plight echos that of the many Lebanese citizens who have been locked out of their savings by bank restrictions that have gradually tightened since the start of the financial crash in 2019.
On Tuesday, a retired diplomat and honorary consul of Ireland, Georges Siam, carried out an all-day sit-in at a bank in the suburbs of Beirut to recover his savings before eventually reaching a compromise.
Almost simultaneously, at least two other armed bank heists took place in separate branches.
They included one by a retired policeman who held up a bank in eastern Lebanon to demand a money transfer to his son in Ukraine to help pay for rent and university tuition.
Lebanon's banks had closed for a week after a series of heists on September 16.
The holdups reflect savers' desperation three years since Lebanon's financial system collapsed due to decades of state corruption and waste and unsustainable financial policies.
Three years on, the government has agreed neither on a financial recovery plan nor enacted reforms deemed vital to get Lebanon out of the crisis. While the government says it is committed to reforms, the International Monetary Fund says progress remains very slow.
Bankers and ruling politicians have objected to recovery plans drawn up by governments, prompting criticism that both have blocked the way out of the crisis.
Without a capital control law, banks have imposed informal restrictions on dollar withdrawals.