Amy Gunnoe of Leawood headed to workout at the fitness center Wednesday morning at the Jewish Community Center in Overland Park.
The JCC reopened Wednesday after Sunday's shooting left two people dead.
William Lewis Corporon, 69, and his grandson, Reat Underwood, 14, were killed at the center on Sunday.
Terri LaManno, 53, a Kansas City mother of three, was later shot outside the Village Shalom senior living facility.
White supremacist Frazier Frazier Glenn Cross Jr., also known as F. Glenn Miller Jr., 73, of southwest Missouri, is in jail in Olathe facing capital murder and first-degree murder charges.
The Jewish Community Center and Village Shalom will host an interfaith memorial and celebration at 10 a.m. Thursday in honor of William Lewis Corporon, Reat Griffin Underwood and Terri LaManno. U.S. Attorney General Eric Holder, Kansas Gov. Sam Brownback and Overland Park Mayor Carl Gerlach are among those scheduled to attend.