The only response that’s reliable across doors, sites, and institutions is the door actually unlocking, which you may or may not be able to discern when already opened. Do you know the beep and light pattern by heart for valid credential vs. recognized but unauthorized credential vs. bus pass at every door you use? Each one in my office is a bit different, my apartment is something else entirely, in college they were uniform within buildings but different across buildings.
Electric mortise locks and strikes will click, though sometimes they are held in unlocked state for a few seconds so you won’t hear a second click, or the second click might be reverting to locked state. Depends on hardware and configuration, and maybe a what the person in front is doing with the handle, and when/whether the exit sensor trips. Different things on the door can make clicking sounds, they’re a bit different from each other, but pretty close. Magnetic locks, forget it. Sliding doors, forget it.
I’m an engineer interested in security, I pay close attention to these systems, I’ve run their cabling and installed their admin panels, and I doubt I could tell even if I were actively paying attention.
