I have some good news...

He run away from his room again, and after hiding under the bed for a while he went down-stairs (15 steps!!) to drink from the water fountain... I guess regular water ball are not enough for him... there are two upstairs.

So he drunk a lot of water and even agreed to lick some of the gravy of the wet food I gave him, then went back up to hide in his tunnels.

I'll try more food later...