I feel like slapping her might have been a bit extreme for scolding, but given the elaborate web of lies she's sewn into her character (such as her teleport power's "limitations"), I can at least see and understand the concern from him.
Yeah, I'm not sure there is a circumstance where I would ever actually slap one of my children; probably because my parents, who were Boomers, absolutely slapped the shit out of us for stupid shit.
That said, I don't know if this kind of shit is normal in either Japanese culture or in the isekai culture; from context clues, I would guess that it isn't, and that he is
super upset.
I would be, too; if one of my kids was sacrificing their lives for some trivial shit?
Wait, they have jobs, so... I guess they kinda are... but, still; I'd be upset.
Anyway, dad; don't slap your kids... but maybe she'll pay more attention, now.
Even if we all know that this just means she'll just hide it better... lolz...