You can't leave him on the lift and wait for rain. Even if it doesn't rain, they'll get bored and walk away. If they get bored while it's rising, well, it's no different, they'll walk away.
There's a time limit on how long they can stand still doing nothing.
We must put them on the platform as soon as the rain begin!
As laurence says, you have to put them on the platform
when it starts to rain, not put them on the platform and
wait for it to rain.