Don't work in a hospital so don't know how they work it there.
Here's what I do. If I have access to a microwave, I keep the QF one of those BIG coffee cups. Tell the tech you need a cup of coffee because I'm not ready to pee yet. Nuke the cup for 10 seconds, and then when the chance arises I move the QF to my crotch. Also you can stall the UA by again just saying you're not ready to pee yet, activate the heat pad in your pocket wrapped around the QF. At the first opportunity I move it to my crotch. Pickup some cheap heat pads from the dollar stor and practice to see how long it takes to heat the QF up. And just be relaxed, nobody pees on command and you're getting paid by the hour so there's no hurry.