Instead of doing this, turn right and crawl into the vent. On the level where you first encounter the Trandoshan Elites (the ones with the minigun), just before you find the elite there is some debris you can blow up. All current weapons will now be fully reloaded. An explosion will confirm correct code entry. Pause game play, then press Y(2), X, Down, R, L, R, Up. The shocking effect on droids is the same as if an electronic detonator was used. Want to shock a droid for free? If you have a concussion rifle on hand, use its melee strike to stop and drop a droid in hand-to-hand combat. This should shut them down or put them on the ground. Throw two electric grenades and fire a quick bust from the DC-17. You should also use your DC-17's anti-armor attachment. Once they are being shocked by the EMP, throw Thermal Detonators to deal extra damage.
Use your EMP grenades and concentrate your men's fire on them.
If there is more than one Droideka, stand so that you are in line with as many of them as possible so that the others cannot see you. Kill it with melee attacks to save ammunition. To kill a Droideka easily, stand as close as you can to it, and directly in front of it (between its gun arms).