What do you think is correct?
1. that's the park that they ate lunch.
2. that's the part that they ate lunch in.

That’s the park where they ate lunch

Explanation:

Personally it sound more correct to me

"get off of your lazy bum and come running with me or i'm dumping this pitcher of water on u " u say with a smile. she thinks your joking so she ignores you about 10 seconds later shes screaming wile water is dripping everywhere you say "here comes the second one! " then you here her say okay, your such a j e r k ! ill be ready in 5 put the pitcher down " she say in an angry tone. and you smile in victory

good enough?