Going into that room is useless until Mayscape apartment update comes. And the safe one was suppose to be hinted in poker game conversation with Rose. But that one is little messed up and will be changed in future. But I will give you hints anyway.
Hint to room :- DAHLIA
Hint to Safe (It has Luna's ragged cloths):- Check the Asylum map again. The note is there until sunflower city update comes.