Musk carries a sink into Twitter headquarters: What does "Let that sink in" mean?

Everyone, it's four o'clock in the afternoon now. Are you still slacking off at your desk? I've already slipped away. Just now the boss was in the meeting room holding a meeting, saying we're going to collectively march into Douyin and build a persona. He asked me, Little Yang, think about it, what kind of persona are you? He said the company wants to build an emotional-type persona. I said, I can't do that, I'll just build a parent-child-type persona, like how to educate a silly son. The boss said, that works, parent-child has a lot of potential. I said, boss, I need to go pick up my youngest son from school now, I'm slipping out first. The boss was very surprised, and then I ran off. Then, speaking of this account, he said, you need to watch the trending topics on Douyin more. I said sure, then let me first go see what's trending on Douyin today. Today's Douyin trending topic is Musk—didn't he buy Twitter? So he carried a sink and walked into the lobby of Twitter headquarters. Then everyone asked, why did Musk carry a sink? Think about it, what is a sink called? It's called a sink, right? No no, he's not job-hopping, rather, a sink is a sink. So there's an English phrase called let that sink in. What does it mean? For example, if you've filled a whole basin of water, you want to let it slowly drain, slowly seep down. What does this metaphor mean? It means you said something very shocking, and then left a person standing there dumbfounded, letting them slowly calm down—that's let that sink in. Just like when I just told the boss, I'm going to pick up my kid, bye, and as for you, let that sink in. Oh, it's raining. When I was leaving just now, the boss even asked me, look at how overcast the sky is, do you want to take an umbrella? I said no no, thanks, bye. Then I slipped away, and I didn't expect it to rain so soon. Do you think that's pleasant? Not pleasant. Oh, I really didn't expect it, out of the blue—let that sink in.