Fou-Lu in a berserker rage is no way gonna have enough wherewithal to think 'I gotta fly over these boxes'.
If I were in a berserker rage, and I could turn into a dragon and fly around to kill things, I sure as heck would. Especially because it'd be faster than going by land.
No doubt she can shoot as she's running for it. Which'll wind up plowing her right into Big Boss + Master Chief, and then she's kibble. Especially if she's paying attention to the dancing naked guy/girl up there, as indicated above
A naked dancing babe isn't going to have durability. She's OHKO-bait, and then KOS-MOS can go back to firing at the other enemies. Also, as noted, her combat AI will prevent her from acting suicidal like you suggest -- after all, if she gets killed, she isn't getting any cheese.
Duke raging with the power of Saxton Hale is not gonna go 'Man, I need to fire up my jetpack and FLY over there'. He, too, is gonna charge. And get blown up
You're misreading the ability. The version used on allies doesn't cause them to be dimwitted, only the version used on enemies.
And Bryan's a homicidal loon, so assuming he'd gain some magic tactical genius is kind of silly.
You don't have to be a "tactical genius" to pull out a gatling gun and start blasting enemies with it.
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another place and time, without a great divide, and we could be flying deadly high