Can you fairly quickly get a Visa-on-Arrival in Cairo Airport around midnight?

Based on only one instance that I can now remember (I suspect I have forgotten others, though more recent, for being such 'non-events') at shortly after 2 a.m. the VOA process took me less than one minute - I was presumably one of the first off the aircraft. However even less than one minute was enough time for others exiting the aircraft after me to have beaten me to Immigration, where there was a queue, so presumably not many passengers required VOAs.

From memory there were two VOA counters available but only one in use. So if one of the last to disembark it may take quite a lot longer. However I doubt that a little over two hours earlier (ie midnight) would have been much different, unless other aircraft were then discharging passengers.

It might have been at a time when few tourists were visiting Egypt and hence most of the passengers were Egyptian nationals.

Even had the VOA process taken a lot longer I doubt I would have left the airport any later, the delay is usually for luggage so how long to get to the carousel makes no difference.

This is exactly as I remember it:

right down to the bypass gate between 'Passport Control' and 'Emigration' attended by a couple of loiterers and with a stream of people passing through it. The only difference is that the narrowing of the vertical corridor appeared to be greater than shown on the map (maybe because I'd turned sharp right to reach that corridor so turned into what is on the map its left side, hence needed to zigzag at the narrowing.) The vertical corridor was quite dark, but 'Emigration' and its holding area less so. 'Banks' (the two counters) was where I exchanged £10 or $15 for a receipt filled in by hand. I think I may have received a few coins in change.