I'd just disable the guns, remove the bolts/barrels, and store the bolts/barrels somewhere remote.

It takes seconds, it renders them all useless, and is totally legal since bolts/barrels are just chunks of metal.

Or, I'd just bring them to a buddy's house and leave them in their safe.

Wouldn't ever cross my mind to just leave fully functioning, unsecured firearms in an unlocked closet of a hospital...