A LOT help for Firebase

Hello thunkers!

My Project -
I am making an online tag where 1 player runs and the other player needs to catch. But it cannot happen in 1 area, it needs different rooms. And i also need to check if there is a play playing or not.

My Problem -
I am having problem storing the X and Y location in a firebase. Receiving part I will make after I complite the sending part.

Link of My Project - Thunkable

Guys I debuged a lot and found errors, no need to reply now!