I'll be a sec
The phrase used by someone who knows they are gonna come back 2 hours later or not show up at all.
Oscar: Right lads, I'll be a sec. Gonna get a quick snack.
Alan: Ok gdem, he isn't coming back, is he?
Theo: Nah ,probably gonna meet up with Hazel
Alan: Ok gdem, he isn't coming back, is he?
Theo: Nah ,probably gonna meet up with Hazel
I'll pop on in a sec
Contrary to popular belief the term actually defines a minimum of 45 minutes passing before anyone will "pop on"
Sam: I'll pop on in a sec.
David: Okay.
45 minutes later
David: Dude?
Sam: Just a sec.
David: Okay.
45 minutes later
David: Dude?
Sam: Just a sec.