Walls and Ceilings - Drying out drywall-SAFELY?

HELP! My "significant other" is using a hair blow dryer to dry out our wet drywall. It seems the upstairs bathtub overflow valve broke and caused a downpour of water to the downstairs closet below. A family member diagnosed the cause and suggested that fans pointed in the direction of the 5 x 8 in. opening in the wall over several days, followed by a misting of bleach water, would save the cost of replacing the drywall. Instead, my partner used a blow dryer set on low, duct-taped it to a vacuum cleaner hose, and dropped the hose down inside the wall. It was left running for 3 hours continuously (mostly unattended). Alongside the hose was a utility light dropped down in between the walls (for extra heat? or light?). When I found the contraption I burned my hand dismantling it. I say this is a fire hazard, but my partner insists it is not. Said something about the heat rising and the ambient temperature. Said that fans would make a "negligable difference" in drying out the walls. Any professionals out there to comment? I don't want my house to burn down. What is the proper way to dry out drywall? Is there any risk in using a duct-taped blow-dryer and vacuum hose?
THANKS FOR YOUR QUICK REPLIES!!!

I don't think it will catch your house on fire, but I wouldn't leave the place for the day with it like that either. It will help some, but it'll take a awhile, (days to weeks) to dry out completely.

I think the best thing would be the fans, did you suck any excess water with a shop vac?