Address the exterior source
Interior drying will not solve an active roof leak. The exterior source should be evaluated and made weather-tight by an appropriate roofing professional.
Watch ceilings and electrical areas
Sagging wet drywall can fail, and water near lights or electrical components creates additional concerns. Keep clear of areas that appear unstable or electrically unsafe.
Dry the inside after the leak is stopped
Ceiling materials, insulation, wall cavities and flooring below the leak may all need evaluation. Hidden moisture is one reason roof leaks can require more than cosmetic patching.