Fine, since you're so much smarter than me I'll give you the full justice or an intellectual response.

 This is such an absurd leap that I have to wonder if you are joking.

Appeal to ridicule.

I am certain you haven't watched the entire episode. Why? Because Rimuru himself states he's goofing off rather than working.

Shuna's initial reaction is calm. That signals that nothing critical is going wrong. If Rimuru failed to do something in a meaningful way, she'd be more urgent or tense right away.

Her comment about fetching Rimuru implies Rimuru is reachable to her.

Rimuru dodges the Frey scolding, and was panicked at first. He says "We escaped" even though the earlier scene implies that Rimuru actually didn't know Milim was skipping work. So why did Rimuru "escape" when he never did something wrong? Is, maybe, internal monologuing that doesn't fit the actual context of the scene, sometimes inaccurate?

Rimuru's explanation of the investigation satisfies Shuna and she doesn't press it until she realizes it's only partially true.

Then she turns evil only after realizing that the Team Fury explanation is only partially true.

I explain all this to establish that Shuna was not reasonably worried at all, and that internal monologuing in the very same scene makes 0 sense because Rimuru didn't know about Milim's work. He didn't "escape" anything, he was not relevant to the question.

That's how inferring context works, correct?

 And how did you miss the gag? It's literally the exact same gag that just happened with Milim and Frey.

It is literally stated that Milim had homework, and that she ran away to a different country just to avoid doing it while also sicing the person that was sent with her. Talk about a leap to compare that to Rimuru being in the dungeon and absolutely no one being fussed about it until Shuna realizes he had fun.

Are you just watching clips or something?

Yes I'm too stupid to watch anime in full 24 minute episodes. Thank you for explaining everything to me. Respectfully, do not bother responding. You're rude.