Ok, anywhere else.
Maybe the Mafia preferred to hit him in the corruptible hellhole.
The local cops seemed to have something up their sleeve when they saw the helicopter come in. They may have known.
We're they in or out of the tavern when Roy was inside?

"Managua??? (expletive deleted), there's no way I can go to Managua."
So maybe he wasn't going to Managua.

I always wondered why they returned to the place at the end. Why not go to Managua from the oil field? It's not like Jackie had a suitcase of belongings he just had to get before leaving for Managua.
"Two more swords and I'll be Queen of the Monkey People." Roseanne

I actually think this is most likely. The film was about the cruelty of fate, and having Scanlon betrayed by an apparently trustworthy man, and then killed by his
friend
, after his terrible ordeal which he barely survives, is a fitting expression of how unforgiving the universe can be.
I suppose, then, that Scanlon's close-up after being told that he'll get a cheque is the moment he realises that he will never get his money, that he'll never be free of this hellish place. He may even suspect that the oil company will try to kill him now that they're finished with him. With nowhere to go and nothing left, he has a final dance before fate puts a bullet in his head.

I think his intention was never to give the money. He was just giving the drivers false hope to make them work for him. This is why he did not give the cash as promised, but wrote a check. Taking the check to a bank would result in the drivers getting arrested because they would identify them by fingerprints. All of them were running from the law or mafia in one or the other way. He could also have called the Italian mafia about the Jackie Scanlon character.
I only ask to be free. The butterflies are free. - Charles Dickens

I think he was on the level with them. He seemed like an honorable man.