As far as I know, the Bombs in Haukke Manor (normal) can not be aggro, it will fixate its target on whoever turned off the light pedestal. Usually when I'm with a pre-made group helping new players to the dungeon I'd ask the healer to stay off the switching duty and leave it to the DPS and me so that the healing doesn't get interrupt. Tank close to one of the switch and have DPSs take care of 3 switches but like people above said, the Bombs die fast anyway so just focus on the boss and grabing the adds when they spawn.

This is just how I do it but I'm sure a healer could also just kite if they choose to especially if you have 2 range DPS in the group, there are other options.