Noob Questions (a few about general gameplay)

Hey Guys!

I have a few noob questions about the different league? mechanics in game.
im gonna try and explain what i mean as much as i can.

so, first question.

Lets say i open a map with a breach in it. Is it best to clear the map first, kill all the monsters, and then open the breach? I guess what im wondering is, if i dont clear the map first, do the "map" monsters contribute to the breach being open longer, or am i gonna spend time on killing monsters that dont keep the breach open? (i dont even know if that is how breach works)

and the next question in basicly the same, but if i open a map with delirium and breach, do the delirium monsters counts towards keeping the breach open longer? (it seems that killing breach monsters adds to the delirium counter from what i can tell)


im at a point where im in between t14-15 maps, i cleared all the atlas points, but im not facerolling t15 and above maps yet, so i gotta be mindfull of how i play the valuable maps..

i hope i made the questions clear enough so you can understand what i mean and what im after