"Hey Brad"

This moment caught my attention on a second watch, but even on a 5th watch I haven't been able to figure it out.

When Abe wakes up in his apartment after they are experimenting with the box, Aaron calls him, tells him it's 7 pm, and asks him if he still has the kids there.

Right before he goes out, he mutters "Hey Brad" to himself. It feels almost like he's trying to recite something he's said before, and he's practicing before he goes out.

Has anyone noticed this?

The thing that doesn't make sense is this is long before they do their trips. This is the first time they stabilize the box. Is there a chance that Abe has created it earlier than we think?

Or is this just character development? Are we just meant to think that Abe is an extremely meticulous person that thinks absolutely everything through.