Waste Not, Want Not

You do not need to run multiple times to get that. Normally finish your scenario then you can just slack and check the buff spawn places every 5min. They continue to spawn randomly at spawn points.

Once the three weapons are activated (stage 5 I believe) You can select each of them. You do not need to use the weapons for the achievement credit, just select them.

The power ups are scattered around the instance. I have seen them under the burning huts, in the base of the towers and hidden in corners! Grab any close ones during combat and run around after the others leave the instance and get the rest. You can collect them after the scenario has finished. They generally look like a chest with a symbol (appropiate to the buff) floating above them.

Make sure you are NOT mounted when you pick up a power up, it will not count if you run over it on your mount.

Make sure you check back up the ramp near the starting area and outside of the fort also. They are not just confined to inside the combat area.

I spent over an hour inside the scenario after it was over finding all the points I could. These are all the ones I was able to come across once I started noting the locations, although there may be one or two more. (I recall one in the open that never spawned again...)

If anyone finds more, please respond to this post and I will update it with the additional information.

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• 26.9 28.6 Inside burning tower by the teleporters
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• 27.3 25.6 Atop the hill in the start area (where the flight master usually sits)
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• 28.1 38.4 Inside burning tower west of the southern gate
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• 29.3 38.3 By the boxes to the west of the southern gate
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• 31.8 38.6 Inside the burning shelter just east of the southern gate
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• 33.9 38.6 Inside burning tower south of the eastern gate
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• 34.0 37.2 Under an awning on the south of the building by the eastern gate
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• 34.9 31.3 Under the northernmost lamp post inside the eastern gate
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• 35.6 32.8 Inside the burning building north of the eastern gate
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• 38.3 33.6 On the cart outside the eastern gate
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• 38.8 37.5 Between the two oil storage tanks outside the eastern gate
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• 45.0 29.0 Under the windmill on the island ont the eastern gate
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There seem to be four power-ups available at any given time (in my experience) and they take a few minutes to respawn -- once I got good at collecting them and could grab them all in a couple of minutes, it would be several minutes more before any new ones showed up.

Each location can spawn any of the power-ups, and the power-ups do not spawn in any order except for RNG-induced patterns. (F'rinstance, I needed the speed boost as my last one, and seemed to see nothing but cooldown power-ups for the longest time. After clearing several complete cycles the next four I found were all speed boosts. RNG can be a cruel mistress.)

They will all show up, though... eventually. Be patient, and keep looking!