No (if you had I wouldn't be able to make a new gas color)

Unbeknownst to you, because you were focused on trying to determine how Nicole will react. Your little "I'm scared too" spiel had the smoke pouring out of your mouth just as fast as your words were. Nicole starts backing up, her eyes dialated in fear, until she nears a cabinet on the wall beside her. She glances over towards a tray on the counter and picks up a scalpel, she waves it around in front of her panickedly. "S-s-stay aw-way from m-me, you freak." Nicole stutters trembling, she's clearly terrified beyond a point you'd be able to calm down without using your newfound ability.

Unfortunately you don't know a way you'd be able to "gas" her at this distance. Since you aren't sure if holding your breath would produce enough of a build up to either blanket the room, or cross the distance before dissipating, and you fear that trying might agitate your headache or cause something worse to happen. While you're considering your options the smoke you'd spewed thins out and Nicole starts to come at you with the scalpel. You back away fearing what the clearly unstable woman would do in order to protect herself. Nicole rushes towards you, the scalpel gleams in the fluorescent light, and your adrenaline peaks.

"STTOOOPP!!" You bellow out in a deep guttural growl. Your voice sounding inhuman as thick dark black fog churns out from your lungs, your vocal cords reverberating as the inky black smoke pours out. Seemingly with a will of its own, the smoke condenses into a near tangible form and rapidly travels up into Nicole's nostrils. She collapses as the black gas bores its way into Nicole's body until none is left. You watch stunned as her veins bulge black, and her skin turning ashen.