I honestly am puzzled what good hand warm liquid might do to frozen door.
Door has quite lot of mass, metal is rather good heat conductor, so small amount of such liquid would probably just froze it even more as one can apply only so little amount of lliquid at given time, there will be no mass at all in liquid and thus no melting effect (unless one has serious organ malfunction that results strong acid being produced instead of urine).
Also pouring water to door will have rather similar effect, it just does not smell as bad (hopefully), so idea to urine into plastic bag is much better, keep your urine in a bag against lock for some time and as it has some mass there actually can happen heat transfer towards lock and there is at least slight chance of success.
Still near boiling water is much better method as it will contain tons more of energy compared to your urine in a bag

Volvo 360GL -88 -under restoration-
Volvo 343DL vario -81 -running-

Volvo 240 Diesel -83 -undecided-
Citroen ZX Dturbo -97 -daily-

