League-of-legends – Can you leave your base without being spotted in Dominion

From what I have read and played, the following actions decrease nexus health :

• Controlling more capture points than opponents decreases Nexus life over time (x damage per 5 seconds for each point you control IF you control more points then enemies)
• Killing an Enemy champion deals immediate damage (-2 life to nexus if nexus life is above 100)
• Achieving a secondary objective (quest) deals immediate damage (-20 life to nexus) and gives your team a buff (like Nashor in normal mode, except not the same buff). Those secondary quests appear randomly and consist of capturing a specific capture point. These quest spawn for both teams at the same time and always concern two Capture points next to another.
• Point Neutralization and point capture (-3 and -2 life to nexus if nexus life is above 100)

If they have a lot of HP, have your ranged champion(s) shred away at it with Kitae's Bloodrazor ( deals 2.5% of the target's maximum HP as magic damage -- basically, it's a weaker version of Madred's Bloodrazor. more info here: http://www.mobafire.com/league-of-legends/item/kitaes-bloodrazor-128 ). This should be purchased by a ranged champion with a high attack speed. Hit-and-run harass them until they're too low to defend (or until you can score a kill on them).

Kog'Maw would also be an effective counter, especially with Kitae's Bloodrazor, since his W skill is essentially a Bloodrazor in itself, and because his longer range (and great synergy with items like Frozen Mallet) will allow him to harass even harder. And it goes without saying, but his ultimate is another great way to chip away at / drive out those champions who like to camp at their turrets (also note that his ultimate is great for defending as well, since a single hit from far away will stop a capture).