on the top floor pastthe guards in a scanner
you open a lift with it
You get the key card from inside the Silph Co. and head to the 5th floor via the elevator.
The card key is located on the 5th floor of the Silph Co. building in Saffron City.
You find the red key card when you chase the thief on the scooter. You don't use it right away. The key card opens the door to the Black Widow's art room, where you complete the game. (You need the key from the curator of the Museum to track her down.)
you don't, dummy.
The Card Key is located on the Fifth floor in Silph Co. Clear at the bottom by a Rocket Grunt.
on the fifth floor in the thick hallway
To get the card key in Pokémon Fire Red you need to go the 5th floor in the Silph Company. You will find the card key after defeating the Team Rocket members.
When the Black Widow catches you , you will have to pass the guard and at top you will use your card
in the castle
After you chase the guy with the scar, you will see that he dropped his key card. Pick it up. This is on Counterfeit Island.
The red "Black Widow" key card unlocks a door in her secret lair (the last part of the island quest). Once you pass her guards, the card opens her secret treasure trove of stolen art, where the final battle takes place.