Modes use Boolean "or" for the triggers. I have a Mode that mutes the phone at doctors' offices. This Mode has several different locations as triggers.
There are times when I have 2 or 3 Routines running and I haven't noticed any unusual drain on my battery. It may depend on which antennas are turned on or what the Routines are actually doing. (I have a couple of Routines that keep the screen turned on in certain circumstances. I imagine that would definitely have an effect on the battery.)
