with sniper character
u have to press "G" to switch from grenades to droid recon, then press the secondary fire. U will be taken into the droid view.
u can make fire and before their time is expired (check the bar) u should make them explode with secondary fire.
U have only 1 droid so i suggest to keep your sniper character near fire ref.-towers.
droid recon can switch to 3d person as well.