Wally, Barry and others in “Unfinished Business”

Wally

Okay, so you ran back in time and made a copy of yourself?

Barry

Well, uh... basically, yeah.

Jesse

It's called a time remnant.

Barry

It's not... something that I can do every day, but I needed a way to draw the Time Wraiths out of the Speed Force, hoping that they'd be more upset at what Zoom had done than they'd be at me.

Joe

[to Iris] Is that what I look like when they start talking about science?

Iris

Pretty much.

Joe

Don't worry, Wally, it'll get easier to understand.

Wally

But how does that even work?

Barry

Same way Zoom did it. I ran back in time moments before I left. It's the only way I could be in two places at once.

Wally

[still a bit confused] O-okay, so the-the time remnant, it's still you.

Barry

Yeah.

Caitlin

But he died.

Barry

I...uh, he was willing to sacrifice himself for all of us.

Iris

That's how much he loved us.

Wally

You know what, we'll just forget about it. Uh, Barry, I'm glad you're okay.