"De ambulance gaat naar het ziekenhuis."
Translation:The ambulance goes to the hospital.
In all honesty most of those pronunciations are exaggerated and you can hear that they are trying hard to pronounce it as clearly as possible. In everyday life you would have to try hard to find someone to pronounce it that clearly.
Here are two video's with normal speech:
E12theK - for some reason duo is not letting me reply to your post but I trust you will see this anyway. That the people pronouncing words on forvo.com et al are trying to pronounce as clearly as possible is an excellent point and one I hadn't thought of. Nevertheless, the pronunciations in the videos you offer did at least have a hint of a second syllable, which sounded something like "uh," but the robot skips the second syllable and goes from "ziek" to "huis" as fast as the ambulance goes to the hospital, which is why we students bring these things up.
Regarding your point that there is no "uh" sound in this voice. I personally can hear it. Perhaps it has to do with the device or perhaps it's easier for me to hear.
El2theK, with headphones and a lot of imagination I can just make out a fragment of a second syllable, admittedly not much more than the sound that would be made naturally if the word were actually written "ziekhuis." Anyhow, this is splitting hairs. At least there's much less likelihood now that I will ever forget the Dutch word for hospital!
Apparently not always, and it depends on the word: https://en.wikipedia.org/wiki/History_of_Dutch_orthography#The_spelling_reform_of_2006_.28The_Netherlands_and_Flanders.29
I remember finding a clearer explanation of what's going on with -en- ages ago, but haven't been able to dig it up, unfortunately.