Invisigal fights pretty similarly to Mecha Man when he's out of the suit.

Maybe this is just too obvious to state but it came to me before sleeping.

When Mecha Man breaks into Shrouds warehouse, he relies on stealth without his suit. He chokes people out from behind or sucker punches mooks. When Robert can't get the instant knockout, it's a chaotic scuffle.

Despite the shit Invisigal gives Robert for having no powers, this is basically her strategy too. She doesn't have any special offensive or defensive powers so besides using her invisibility to make the stealth portion easier, she still fights like a normie. If she can't get the knockout blow during the ambush, her tactics are just running around trying to survive.