Assuming you don't have more important targets, hold your ult for when Vivian uses hers. Tag her with a bit of damage, then ult. Be wary of supports being nearby, or if she's running the Scapegoat card, as either will likely shut down the kill
Try to keep track of Androxus ult, particularly when your ult is either ready or active, as Andro can burst all his ult shots on you to kill you and/or destroy your drones.
If you suspect Mal'Damba has his ult ready, try to space yourself a bit from the rest of your team. Dread Serpent will knock you out of the air if you're flying, and its hitbox persists for a few seconds after it triggers.