Batman flies after their escape boat with the Batplane, towing Robin along on water skis. Which makes perfect sense in a world where people make batteries out of pennies and salt water. In fact, I'm not sure why Batman didn't just putting giant pennies in the water and friggin' electrocute the Penny Plunderers. Must have seemed more fun for the artist to draw Robin landing on the gang's faces with his water skis. Besides, it would be impossible for a flying craft like the Batplane to hang something like a Giant Penny out the window. Or so you'd think; more on that later.
So, since it's pretty easy to escape a man in a plane and a boy on water skis once you're on land, the Penny Plunderers go to ground at the docks. UNTIL Joe has a bright idea, as bright as a copper penny:

"No, let's not try to escape Batman; let's try to capture him. Just like I did two pages ago, when I failed to kill him because I chose to set up a death trap rather than shooting him in the head. Why? Because I'm not just an obsessive gangster; because I'm a VILLAIN, goddammit, and I'm gonna act like one! Furthermore, just to show how unafraid of Batman I am, I'm going to use MYSELF as bait. Then I'm going to assume that you two losers, who just had the snot beat out of you by a teenager on water skis, are going to be able to "bottle Batman and Robin up" by, I don't know, sneaking up behind him or something, rather than just getting your asses kicked again by a boy in swimming trunks. And in the process I'm going to lock myself, unarmed, in a room I can't get out of, and call it 'trapping Batman & Robin'; I AM A GENIUS!!!!"
Joe E. Coyne: Genius At Work.
Oh, but the room in which Joe decides to seal himself lies deep with the Warehouse of Irony, for it (highly improbably) has a payphone in it. Which of course Joe can't use, because....

The irony of this is not lost on Joe.
Face-melting irony, in fact.
Although the irony not might be lost on Joe, Joe is certainly lost on the irony.
"Betrayed"? MMmm, no, I'd say it's more like you chose something worthless and nearly useless as your "crime symbol", Joe. Appropriately enough. But nothing is ever YOUR fault, is it, Joe?
In case you might have missed it, the caption box underlines the fact that the cause of Joe's death is COMIC BOOK IRONY.
PLEASE tell me this kid grows up to become The Penny Plunderer II.
And Joe Coyne goes to the electric chair, which I really really prefer to imagine being hooked up to two giant pennies immersed in salt water. Joe's story ends here; but the Giant Penny's story goes on!!