This achievement is so rare to get. So I'm happy to help if you need this. Read the instructions on how you can get it...

1. You need to leave a comment so I know if you'll need it.
   
2. I'm going to make a room for you, and I'll choose Crash Course for fastest respawn, and fastest way to get the achievement.
   
3. I'll play as Infected because I need to be Boomer in order for you to pass you (and if some players will join).
   
4. Just stand near on the dumpster and wall (where the truck is parking), then wait for me to boom.

Here's the proof on how I help a player to get the achievement:

There you go! Don't forget to give thanks, it would be appreciated and motivated for me to help others. :D

For other achievements, I can also help you out if you're willing.