Joseph Narrative (2): Why Judah proposes to save Joseph again?

For the previous story (1), see here.
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As Reuben proposes, the brothers don’t kill Joseph by themselves but instead throw him into a pit. They let him drowned and leave the place. And they start having a meal. 

25  Then they sat down to eat; and looking up they saw a caravan of Ishmaelites coming from Gilead, with their camels carrying gum, balm, and resin, on their way to carry it down to Egypt.
26 Then Judah said to his brothers, “What profit is it if we kill our brother and conceal his blood?
27 Come, let us sell him to the Ishmaelites, and not lay our hands on him, for he is our brother, our own flesh.” And his brothers agreed.

As they are having a meal, they find a caravan of Ishmaelites coming from afar. And once again, Judah proposes not to kill Joseph just like Reuben did. But Joseph is already in the pit, and at this point, we must assume that the brothers thought that Joseph is already dead. If they knew that the pit is without water and Joseph is just having a difficult time in the pit, it is strange Judah said not to shed his blood. Moreover, if Judah only intended to put Joseph out of the pit by suggesting to sell him to Ishmaelites, his plan utterly fails. According to v. 28, Midianites are the ones who save Joseph from the pit. It might have been natural if Judah tries to sell Joseph right after the brothers’ conspiration to kill Joseph at the outset. Considering the context, Judah’s attempt to save Joseph in these verses is very unnatural.

For the next story (3), see here