The choice, explained by two points of view.

This is why I love Homestuck. Jade’s story was ridiculously opaque to start with, and John and Roxy’s descriptions of their stipulations are pretty vague too, but put them together and you get a much more cohesive idea of what is going on. John agreed to take himself to the alpha timeline with his retcanoning power and all his knowledge, but the cost was Jade’s suffering (possibly the rest of the team too, we don’t know what happened between Jade meeting alt!Calliope and this one). 

I find it interesting that two of the most caring, selfless characters in the story essentially had to inflict suffering on others. They didn’t really know that’s what they were doing, but they did it all the same. 

I am really curious and also really do not want to know about how Roxy dies. I kind of get the feeling that Jade spending three years alone is the equivalent to John’s suffering over all his friends dying–and that Roxy just dying won’t cause the same pain as what she went through, but that somebody will have to go through losing all their friends/spending three years completely alone because of her death. I hope not, though!

This was a great fucking upd8.