I guess it might depend on the source of the explosion. If it was something scripted in the mission (like calling down artillery, or detonating a pipebomb) then you could script (or eventHandle) a trigger onto the target position (with a suitable radius) and have any enemy (or just anybody) in the blast zone get a setSkill to 0 or something.
You could possibly even make an array to remember what their skill used to be, then wait 15 seconds and start stepping it back up.
Wouldn't want to try it for a fired eventHandler on, say, all AT missiles, or tank shells, or grenades, etc...