I just saw the movie (advance screening). It's awesome.
Place your faith in Ryan Reynolds.

I think they should have had Barry say something specifically along the lines of "She will get involved if she knows and THAT will put her in danger'. Ignorance puts her in danger, but she isn't the type to know and not get involved - I think if they structured the argument that way, there would be a lot less…

Or he thinks he changes the timeline enough to alter his death when he kills Wells - he doesn't know about the Earth 2 drama. Or thinks he IS that Wells and they don't know it… thus he has survived… Tina McGee can get him back to his time with the protoype invented a year after all the drama went down, he doesn't want…