I usually cover my team's back on Swat, so the other 5 players can deal with the zeds infront and mostly can deal with it. Because they wouldn't get distracted when getting attacked from the back and it's mostly deadly if they did. While I'm covering their backs, I simply start off using the dual 9mm pistols for the first 3 waves under these skills.
-Heavy Armor Training
-Close Combat Training (110% 9mm and knife bonus damage)
-Supression Rounds (Extra ammo doesn't work for 9mm)
-Assault Armor (At FIRST wave then change it to Cripple)
-Rapid Assault
So the task is to try and get 1.5k dosh or more until the 4th wave. So you can purchase the Vector and if you have a little more left, buy some extra ammo and then you'll slowly build up more dosh and you're aswell ready to kill off some scrakes (They do appear in the 3rd wave in HOE) Also, shift all your skills to the right side if you bought the vector.
Some tips to build up dosh to the 3rd wave
- Only buy 9mm ammo and stun grenades (If you threw any)
- Try not to get hit, spare your armour to the 3rd wave
- Do use the MP7 when necessary (Gorefiends or Bloat are too close for example and be free to use it on the 3rd wave)
After you've got the vector, be free to run around now but getting your team's back is preferrable but it may be boring over the time. You'll also slowly build up more dosh to buy a P90 or UMP and etcetera. But your priority would be mostly stun nades and ammo for the vector and sharing it of course! Over the time, use your stun grenades wisely! Use it when a swarm of trash zeds are surrounding a team mate of yours or use it on scrakes and fleshpounds.
You can easily kill a scrake with a single mag, depending on what level you are and what difficulty you're playing (On HOE, a Level 22+ has enough ammo on the vector to kill a scrake with a single mag) To kill scrakes, is an easy task but be sure to:
-Be on the right level on the right difficult
-Stun the scrake using a stun grenade
-Walk up close quickly, directly aim at the scrakes head and spray your entire magazine into it
And the job is done. For fleshpounds, leave it to the stronger perks. Fleshpounds are more difficult to kill but do try damage it as much as you can while he's raging.
That's it, I'm not good at making guides but I try my best to explain out of my experience!