There are tons of things to do during the ten second rage crash. here are a few:
1) evaluate you/your team's position
2) use (combine/manage/take) inspirations
3) reposition
4) Taunt (not affected by (-damage)
5) Use any other non damage power (if you took hand clap, hopefully with KD proc, now is the time)
6) Use P2W vet reward attacks (blackwand, nemi staff etc) they are not affected by dame buff NOR the damage debuff
7) communicate with teammates. Been waiting forever to say something in team chat about idiot X doing thing Y, now be that time
There are probably a billion more. have fun