For his entire career as a dungeon supplier, it is an obvious rule that they would pay him to enter the dimensional instance. There was consent that by entering his dimensional instance they would pay a fee to utilise his instance and get stronger. Should they die within the instance, they could be revived as it was a contract when they paid him a fair sum of money.
Thus this was the first time he conjured a dimensional instance, the usual mode of payment was not cash but their lives. If they were able to get out of it alive, they would undoubtedly get stronger and if they do not, they would be decimated and so all of their points would be transferred to Jin.
