Is it possible to change the font color of just one Text Label in the Player Text Labels?

The exit label shown on the attachements is unreadable because it is black font on a black background. I see that I can change the font color globally for the player text labels but doing that would impact other slides. Is it possible to change the font color on just this one slide player text label, or have it use a specific slide master slide that has a white background?

Thank you for your help!