Garen Double Ult Zac

I was playing Zac on ARAM and ended up dying to Garen's ult. My passive proc'd but no one killed me off. When I was supposed to revive I died and took 1700 true damage with Garen's ult, only the sound effect happening again. All in all i took 4100+ true damage from Garen's ult. I only had ~3700 hp in total.