The other guides are actually good but I found an even easier way to do this and it's also possible doing it alone. As others have stated, this is required to be done in 1 life, respawns will reset the achievement count.
Hop on the "Big Team Infinity Slayer" playlist, this is your best bet to be able to get a vehicle. The vehicle we will want to focus on will be the Mongoose, it's possible with other vehicles but I found out it's easier to do it with them since pretty much nobody goes for a Mongoose at the start of a game.
Before you get into the actual game, be sure to have the Survivor support upgrade, the Grenadier tactical package and Plasma grenades as your chosen type of these. With the Grenadier tactical package, you'll have 3 Plasma grenades in your inventory from the beginning, which is the exact quantity you need to do the achievement.
Okay, so as soon as the match starts make your way to a Mongoose. Start punching it until it starts to get on fire. Then, before you hop on it, throw a Plasma grenade behind or ahead the Mongoose so as soon as you hop in you have enough time to drive close enough the blast radius for the Mongoose to explode. If you find yourself hopping out of it without dying as soon as it exploded then it means you did it well. Repeat this two more times and you'll have bagged yourself some easy 25G. The respawn timer for the Mongooses/Mongeese is very short and you'll be able to do this without any much trouble or time.
By the way, be sure the grenade doesn't stick to the Mongoose before you hop in because this won't make the support upgrade work and you will commit suicide.