Ignore the tooltip, they're generic 'this is what we think it should take to run' that is a direct display of their normal Portal tooltip. You'll see that all Fireteam Ops activities have a 10-15 minute timer listed, Pinnacle Ops gets varying timers, but ultimately those aren't changed to what they think you should be able to do the Conquest version in. The timer for Derealize has a decent chance of being changed due to the length of the mission, but there's also a good chance that they intend for people to rush-clear rather than slowly clearing rooms so they can be at the boss room within around 15 minutes so they have time (and as a result Revives) available at the boss fight.