[beof95]

This is a multi step one

step one hide the key to the mail box on the top floor of the building (I live on the bottom floor, building has 6 floor + bottom so a total of 7, and no lift and only one stair case with automathic lights)
step two take the key to the flat off the keychain
step three strip naked in flat
step four get out and lock the door
step five drop the key to the flat in the metal mailbox

now you have to go and get the key on the op of the stairway while making sure no one goes out that is above you or goes in that is below you

I ended up hiding under the bottom stairs for 5 minutes naked as some people went to walk a dog but they were just hanging out around the entrence to the building so I couldnt move until the dog finished its business as one of them kept goin in and out of the entrence that looks at the stair way