The decision by a former City Council aide, Viola Plummer, to defy Speaker Christine Quinn and return to work as a volunteer is rankling some council members. Plummer, the chief of staff to Council Member Charles Barron of Brooklyn, yesterday was given a visitor’s pass to enter the building across from City Hall that houses Mr. Barron’s legislative office and those of other council members.

She said she plans to stay on Mr. Barron’s staff as a volunteer indefinitely and will attend council meetings and hearings at City Hall as she did in the past.

Ms. Quinn suspended Plummer after the aide promised to end the political career of Council Member Leroy Comrie of Queens, even if it took” an assassination.” Plummer could have returned to work after the six-week suspension if she had signed a good behavior pledge by Friday.

The chairman of the council’s public safety committee, Peter Vallone Jr. of Queens, said Plummer should be banned for life from City Hall.

“I don’t think anyone who clearly threatened the life of a council member should ever be allowed back,” Mr. Vallone said.

The minority leader of the council, James Oddo of Staten Island, said that anyone who doesn’t behave appropriately at City Hall loses “the right, the privilege of being in our house.”

A spokeswoman for Ms. Quinn, Maria Alvarado, said Plummer’s official council employee card has been deactivated, but noted she is able to visit City Hall and council members’ offices like any member of the public.