Welcome to the world of soft realtime applications. Sounds like this one is just so bad that a) the designers didn't realize that was what they were designing a

Welcome to the world of soft realtime applications. Sounds like this one is just so bad that a) the designers didn't realize that was what they were designing and b) consequently it failed to meet any of its deadlines in the UI domain. One detail I've noticed is that even if you do a shitty job of hitting the deadlines, users will often find workarounds. As long as a critical mass of features respond consistently within the deadlines, users will fiddle around to make the rest work-- even if you tell them directly that it isn't possible. Say the dropdown menus here performed fast enough, but going to the "next page" required a bunch of DOM mutation or something that grinds to a halt for two seconds. I'd bet EMTs would have trained themselves to do branch prediction-- hit the button to change pages before setting it down, hit it again based on what the patient is communicating to the other EMT, and so forth. I've seen users do weirder stuff. The fact that they discarded it altogether tells you how bad the UI was.