One word: SNIPER.
She can't fight what she does see and after the sniper fires, she won't be fighting anything, except maybe to remain conscious.
As GM you are NEVER at a player's mercy. She can only take so many actions in a round, make sure there are five times as many NPCs as actions she could possibly fight in a round.
The D6 rules have a rule for massed fire, the idea being it is more difficult to dodge fire from more than one shooter. Use a house Mass fire rule to have your Bruce Lee wannabe so busy dodging fire she can't attack. PCs never run a story, the GM does. You've got way too many resources to ever have a PC dictate how an encounter goes.
Jem Hadar and Borg have personal shielding, have some enterprising Alpha Quadrant race or group have a crude version of the personal shield. Have it fail on a roll of 1 on a D6 to represent it's fragile nature, but if she's facing 20 thugs with personal shields, she's not going to take out more than one or two of them before being riddled with phaser fire, if you are feeling nice, you could use stun, I personally wouldn't to make the example very clear to the player.
"For to win 100 victories in 100 battles is not the acme of skill. To subdue the enemy without fighting is the acme of skill." Sun Tzu - The Art of War