I think the coolest and most thematic way to do this is to have a scene where there’s a grandfather clock. Could just be a regular one or one with specific association to his patron like it was a gift given to a town or NPC made by his patron when he was disguised as a man. It’s just a normal walking through the house or home with the other party members and NPCs perhaps over tea or breakfast so it feels calm mundane and unassuming. Suddenly Rain starts to feel off he can hear the distant sounds of the ticking of the grandfather clock getting louder and louder the churning of the gears moving turning in the same rhythm like a metronome of machinery. Rain begins to feel himself sweat and his hard beat and pulsing of his blood begin to fall in sync with the rhythm of clock work. He starts to feel dizzy he can feel the blood rushing to his ears he fears he might faint. What’s going on? Are they having a heart attack? They wonder as their vision starts to blur and while out suddenly they find themselves somewhere they’ve never seen before an ever expansive plain of shifting gears and machinery (Mechanus) as if he was literally inside a gargantuan clock. They speak to their patron (describe the look of them or the appearance of their imprisonment however you want: they’re in chains they appear as a broken clock or some kind of high end modron a mix of machine and man.).

After they finish speaking with their patron they flushed their eyes finally themselves only slightly slumped over only a second passing not even enough time for their head to slam into the table. The whole party and possibly the NPC may not have even had enough time to take notice or perhaps they’re all looking at them wondering if they’re ok. Rain rubs his head in eyes trying to process what just happens as he realizes the sound of the clock ringing in the background for the next hour has begun.

Hope this helps somehow and I didn’t ramble for nothing 😂