Can you rescue all prisoners and still get an S-Rank in the main mission?
Yes. Saving all the prisoners + Paz and Chico gets you 24000 points and you only need a little over 60000 to get S rank. The easiest thing to do is just straight line it to Chico or Paz first tranqing everyone on the way taking your time, put them and the prisoners at the cliff side extraction point near the cages and put them all in the helicopter. Take your time and you should easily complete it under 20 minutes. You will probably also need to turn reflex off (so just memorize where every guard is, there aren't that many, and tranq them all before they see you) and not use any checkpoints or get any alerts. Just move slow straight to Chico and Paz tranquing everybody.
There is a difference between "alerts" and when an enemy radios "contact." I still have not been able to stealth that mission though. The enemies go on full alert about 3-4 minutes in, as they find your ship--just too hard after that.
When they go on alert (there is no way to avoid it if you are playing the mission normally, if you speed run it you can finish before the alert starts) it doesn't count against you, and all it does really is increase the guards range of movements, but they are still all on a repeating pattern. So if you need to just observe the guards and see the paths they walk as they will just repeat them.
Thx.
I have some quick questions and google has failed me:
1. What are the question marks in the stats screen? Is it to destroy the Easter Island heads?
2. After you kill the second renegade in the Renegade Threat mission, has anyone had Miller suggest watching the enemy tactics? What does he mean? as I am normally booking it to the LZ. Does this relate to the last conversation when he suggests the two Marines were afraid of something worse than death?
1) The time trials that unlock after completing the missions once and some you'll need to complete the first time trial to unlock the rest.
2) He might say this if you are really slow? Maybe he wants you to pay more attention to where they go so you can take them down easier instead of looking for them all over the level.