In Hollywood, Los Angeles, Peter, who was about to head to Mary Jane's set with the other two, now faced a very awkward problem—if they followed the original plan, with one person luring Mary Jane away while the other two investigated the set, who would act alone?
Under normal circumstances, Mary Jane's boyfriend Harry should have been the one to lure her away. The excuse would have been easy enough to find: he could say he had seen how hard she was working and wanted to surprise her. It would have been easy to lead Mary Jane elsewhere and let the two Spider-Men enter the set to investigate suspicious individuals.
But if Harry left while middle-aged Peter stayed with Peter, middle-aged Peter would definitely ask Peter what the purpose of this plan was.
How was Peter supposed to explain that the plan was actually meant to help Little Green reclaim someone who was his wife in another universe?
And if Peter and Harry stayed behind instead, he would face the same problem. Harry would certainly ask where this suddenly appearing Peter from another universe had come from, and that would inevitably lead to middle-aged Peter Parker's life story—how he and Mary Jane had married, divorced, remarried, and had an adorable little daughter.
And if Peter left on his own, leaving Harry and middle-aged Peter together, Peter did not dare imagine what would happen next.
Peter knew very well that Harry's feelings for Mary Jane were different from Peter's feelings for Gwen. Peter hoped that Gwen would live well whether he existed or not, and Gwen felt the same way.
But Harry had a strong possessive streak toward Mary Jane. Perhaps that was a trait passed down through the Osborn family, but Mary Jane was someone who valued independence deeply. She