If a rune has "Before Combat: Activate to..." and also "During Combat: Activate to.."
I'm assuming you can only activate one or the other during a turn?
There are activation limits. You can activate one "activate" card (with the hourglass on it) during each non-combat phase, one during before combat, and one during each combat round.
So you can activate both the Before Combat and During Combat cards during the same battle.