Have climbed plenty of ladders, including tall extension ladders while holding objects much larger and heavier than a semiautomatic pistol (impact drill, sledgehammer, etc) while wearing a utility belt loaded with other tools. Honestly, it isn’t difficult. Not OSHA approved method, I’m sure, but it’s not difficult, I promise you. As far as having the pistol loaded, of course it would be, why would that make a difference? Also, if the cop didn’t feel comfortable climbing one-handed, then climb two handed until just below the edge of the roof, unholster, pop up with gun in one hand and other hand on the ladder rung. Every handgun drill includes strong hand only shooting for just such a scenario.
You're finally making sense.