By a CC permit holder? By someone legally permitted to have a gun inside a nightclub?
If the place served alcohol, then it was illegal to have guns in there.
This is from Florida's government website regarding guns.
(
12)(a) A license issued under this section does not authorize any person to openly carry a handgun or carry a concealed weapon or firearm into:
1. Any place of nuisance as defined in s. 823.05;
2. Any police, sheriff, or highway patrol station;
3. Any detention facility, prison, or jail;
4. Any courthouse;
5. Any courtroom, except that nothing in this section would preclude a judge from carrying a concealed weapon or determining who will carry a concealed weapon in his or her courtroom;
6. Any polling place;
7. Any meeting of the governing body of a county, public school district, municipality, or special district;
8. Any meeting of the Legislature or a committee thereof;
9. Any school, college, or professional athletic event not related to firearms;
10. Any elementary or secondary school facility or administration building;
11. Any career center;
12. Any portion of an establishment licensed to dispense alcoholic beverages for consumption on the premises, which portion of the establishment is primarily devoted to such purpose;