At this point there is still a strip of adhesive along the bottom of the display that will hold the display to the frame like a hinge. You can loosen this adhesive by working the display up and down a few times.
Lift the display up from the frame and remove it from the iMac.
It may be necessary to slowly lift from one side to peel against the remaining adhesive.
Be very careful handling the display—it's big, heavy, and made of glass.
After the adhesive is cut, it cannot be used to re-seal the display in place. Follow this guide to replace the adhesive strips that secure the display to the rear enclosure.
During reassembly, if installing the AirPort card proves challenging, you can use curved tweezers to help orient the card and insert it into its slot on the back of the logic board.
With the tweezers pointed downwards, insert the points of the tweezers through the screw holes in the AirPort card, next to its antenna connector sockets.
Using your finger, press down on the edge of the AirPort card to angle it until it is roughly parallel to the logic board.
Align the AirPort card with its slot on the logic board, and press the card into the slot until the screw holes nearest the connector align with those in the logic board.
For reference, the third photo shows the logic board removed and flipped over for a clear view of how the AirPort card is installed.