As soon as one of the party moves closer to the grate Knesh's thin reedy voice echoes down,
"Ah you survived your ordeal, I am so glad. But you must forgive me, I am a pitiful old man, you are young and vibrant you will I am sure to go on to win great treasure and renown, but alas such things are passed for me. I am afraid I much renage upon our deal.
I am ashamed to offer new terms, but I must. Give me the treasure, and the leprechaun's head, and I will unlock this and toss you down a rope that you might escape. I'm afraid even nimble fingers will not avail you otherwise, even were I not here with my knives - not to mention you unconscious companion - you could not reach the lock.
The only other way as I understand it is to swim out, but I'm afraid the local scum have been dumping a good many bodies into the water, and I may even have dumped a carcass or two into the waters myself these past few days. You could make it, but I rather doubt it.
So please be reasonable and look at it as charity to and old man. I'll simply lower a rope and you can attach the leprechaun's head, then in turn the treasure. It may take a while, but we have the time I assure you. Then once I am satisfied that the head and treasure are real, and wholly no illusory I will open the hatch, drop you a rope and scarper.
There really are no other boats on the island, I've seen to that. But if you wait a few hours, you are bound to be able to hail someone. I will of course be long gone from Venza by the time you do though, using a different name, and a different face. Nothing but a memory, perhaps I'll become a merchant, or an Innkeeper, somewhere nice and provincial.
But I do go on, pardon my ramblings. Again my apologies, but I needed to rid myself of that accursed leprechaun and I am too old to make another fortune adventuring, so I cannot afford to share the treasure. Chalk it up as a valuable life lesson."