How do I pause the game's timer but allow the player to move?

I'm making a 2D maze game, with a strong focus on time based mechanics. One of the mechanics that I want to implement is a power up that pauses the countdown timer but still lets the player move around while the timer is paused. I have already added a pause menu that sets the timescale to 0. Is there a way to set the timescale to 0, but exclude the player when that happens? Also I want to set that power up to a timer, so that it will only affect the game for a few seconds. Thank you.