> > As it's impossible to leave the building without a key in case of a fire. > Isn't that the case for most doors that lock? You can't leave through my (brand

> > As it's impossible to leave the building without a key in case of a fire. > Isn't that the case for most doors that lock? You can't leave through my (brand new, to-code) front door from inside without a key to unlock it first. Do you live in the US by chance? In my jurisdiction double keyed deadbolts for example are not up to code for residential use, and for those applications the deadbolt must be keyless on the egress side. Logically, this seems sound as you don't want to be scrambling for keys if your house is on fire.