Inject multiple at once

[Laclale♪]

Injection Shotgun wrote:

If you're trained with this weapon and have the primary target class feature, it gains the ranged injection trait, but it only injects a substance into your primary target.

Primary target is known to be Soldier's feature. But there is a fighting style that makes opposite of it.

Close Quarters wrote:

When using a soldier feat, you can treat any two-handed melee weapon you're wielding as having the area (burst 5 feet), allowing you to area fire with the weapon centering the burst on a corner of a square you occupy, and you are unaffected by attacks with that weapon. You can make a melee Strike with a two-handed melee weapon instead of a ranged Strike with primary target or any soldier feat. In addition, you gain the Whirling Swipe feat.

Whirling Swipe wrote:

If your weapon has reach, the burst radius becomes the reach of your weapon. Area Fire with the required weapon, centering the burst on a corner of a square you occupy. You’re excluded from the burst.

Syringe Skewer: The two-handed melee weapon with reach and injection trait.

Whirling Swipe makes Syringe Skewer to be burst 10 feet area weapon while keeping injection trait.

Does it counted as logic hole?

[Dracomicron]

Speaking of 2 handed weapons, I'm amused that you can Whirling Swipe or Close Quarters fighting style an Assassin's Garrote. It doesn't do much, since the weapon is mostly for grappling, but you can hit an area with that little wire.

[BotBrain]

I would say nothing happens. Injection shotgun has its own specific rule for this, suggesting it is an override of the general rule which would be nothing.

The injection trait is annoying here because it says lowercase a "attack" instead of "Strike" or capital A "Attack" which would imply something with the attack trait.

Since primary weapon isn't a true Strike (I.E no damage), I would find it hard to justify allowing it to inject someone without an explicit carveout to let you do it. You certainly cannot inject multiple people at once.