I'm confused on this one. For my "Mission Complete" and "Single-Player Master" achievements, I just need to get the secondary objectives for "Who the hell are these guys?". I know it can be done in Quick Mission, because I did it for "You'll be inserted Solo" and "Codename Farallon".

How many vehicles try to escape, and at what part? And do you have to wait for the purple square to appear before blowing them up? Because there were a few, but I didn't wait - I just GL'd them with Bo.

Its been a while since I played through the single player campaign and I don’t recall all the mission names very well, but if you're talking about the mission I think you are......

When you're first inserted immediately at that point before you move forward past the buildings there's a steep slope to move up, when you reach the top there's a walkway which takes you across the road below. Move up to that area and in the distance you will see a vehicle to take out.

That one caused confusion for many as the vehicle in question is off the normal mission path so you don’t realise you've missed it.

Hope that helps