Fence it off so no one leaves unless in cuffs.
Make it rain 24 hours a day (equivalent of turning on the sprinklers)
Flash bangs every 10 - 30 minutes but random and play the Barney song in a loop at a high volume.
Wet and sleep deprived they will either surrender or off themselves.
thats a lot of work, not to mention water damage, put a tent up and fumigate the building occupants or not.