I initially thought he was just asking the audience to quieten down so he could say his
last words so he could end with a flourish but watching it again I am not so sure.
It's not really the obvious way to signal to the audience. It does seem more like a signal to
someone off screen. Also the card in the pocket is weird. He specifically says he wants to
"finish" where he began with that card.
While the bit with Simon is connected to that trick it is not actually the end of the performance.
This could still be what he meant though. Simply end with it as in it is part of the final act.
But the fact he kept the card in plain sight throughout definitely suggests there would be
a reveal using it. So...
I guess he might have just ran out of time.