It’s fair to say that many in the Call of Duty: Warzone player base want the benefits of the gas mask without its drawbacks.
Call of Duty: Warzone, perhaps more than any other battle royale, really wants its encroaching circle of death to be taken seriously. The gas, as it’s represented in Warzone, is very deadly to those caught within it.
Not only does it hit player HP, it also eats away at their armour. To counteract this, players can find or buy a gas mask that would stave off that affect for few crucial seconds, but not much more.
The only problem is: putting the gas mask on and off – which the game does automatically as you cross into/out of the gas – takes you out of ADS. In the hectic final circles, this can be the difference between winning and losing a gunfight, all because of the second or so it took the animation to play.
Since the launch of Warzone, many players have been complaining about how that equip/un-equip animation has cost them crucial fights. Seemingly by accident, Reddit user RoninMk7 discovered that having the Heartbeat Sensor (a staple in our best Warzone loadouts) equipped, prevents the gas mask animation from playing.
It goes without saying that much like the gas mask, using a Heartbeat Sensor also takes you out of ADS. The difference is minor, but it is there. There’s also the added benefit a sensor offers as far as revealing enemy locations. Outside of that, you’re really only trading one animation for a slightly faster, less obtrusive one.
Infinity Ward previously fixed a bug that caused that same gas mask animation to prevent the player from deploying their parachute, but the developer has yet to make a comment one way or another on whether the animation will be changed for on-the-ground gameplay.
As many in the comments pointed out, however, the animation is necessary to make flanking through the gas more risky, affording players in the safe zone a bit more assurance when they know their backs are covered.