Thalaron radiation is lethal, all the time, every time. They've done this for nearly two years since they gave the Romulans thalaron weapons for Cloaked Intentions.
To avoid it:
1. The mines are laid by a drone. Kill the drone, no mines.
2. The mines, once laid, throw up bright green pillars of light for over 5 seconds before they go off. They have very low HP and can be destroyed in this time.
3. Once they go off, they only hit a narrow circle around them, and the mine is also destroyed. Simply being a few yards away leaves you safe. Your officer can't be counted on to get to safety.