Gears of War 3 Game Guide

Act Five: Chapter 4 – Threshold

Head to the end of the hall to grab the statue. There are frags and boomshots
behind the counter. Call the lift, and after the scene, call the lift again
to grab a poster. Head out into the courtyard for a view either side will be
the same, and then just sit back atop the steps and kill the Bloodmount and
Therons as the mortar shells pound away. After a time they will stop, and that
is the best time to move up. However, on higher difficulties the barrage does
not seem to end, so you'll have to just fight the group ahead while watching
the skies. 

When you do move up the path, you'll hit a bridge and when you try to cross
over a bunch of Therons will rush you from around the block in the middle,
an Armored Kantus will follow, and it may just be hardcore and up that will
have a Bloodmount appear too. On hardcore and up, just toss a few frags, and 
back up to the wider ground where you can dodge the mortars, and the boomshots
from the hotel will come in handy as well. Don't try to move up the narrow
bridge with mortars dropping - bad idea. Just clear it out and then cross to
kill the mortar guy. Grab some ammo and hop the sandbags.

Pick up the mulcher and have it ready to kill the Gunker who will appear on the
right side bridge. You need to kill him first to avoid the imulsion bombs, and
then focus on the stalk pods. Then the Drudges and finish off all the Drones
who will be on all sides. Feel free to kill the Gunker with frags or boomshots
if you must.