How do you handle random encounters if the GM isn’t supposed to roll dice?

I’m trying to deal with random encounters in DW. If my players are in a town, and suddenly decide to go into a random building how do I decide if the NPCs in there like the PCs? In D&D I’d just roll for a reaction and take it from there. Here I feel like I need to decide if the NPCs want to get along with PCs, and frankly I’m not sure what the NPCs think.

Sometimes I just think a roll of the die is exactly I want for my NPCs.