Dr. Newton Geiszler: Fortune favors the brave, dude.
Stacker Pentecost: Today at the edge of our hope, at the end of our time. We have chosen to believe in each other. Today we face the monsters that are at our door, today we are cancelling the apocalypse!
Dr. Newton Geiszler: Oh, my God! This isn't a refuge. This is a buffet line!
Newton Geizler: Move, you fascist!
Raleigh Becket: There are things you can't fight - acts of God. You see a hurricane coming, you get out of the way. But when you're in a Jaeger, suddenly, you can finally fight the hurricane. You can win.
Yancy Becket: Don't get cocky, kid.
Herc Hansen: We're not going anywhere! Now, you and I are only thing standing between that ugly bastard and a city of 10 million people. Now, we have choice here, we either sit and wait or we take these flare guns and do something really stupid!
Stacker Pentecost: Haven't you heard, Mr. Beckett? The world is coming to an end. So, where would you rather die? Here, or in a Jaeger?
Stacker Pentecost: One, don't you ever touch me again. Two, don't you ever touch me again.
Chosen answer: Most likely they only use it when they know they have a guaranteed shot and won't waste it. It can't be reloaded that easily. Like having one bullet to kill a zombie vs a sword so go for the sword save the bullet it's more valuable. That's typical military tactics. Possible firing whatever weapons could cost a ridiculous amount of money just like missiles do. It's not exactly like Yeager weapons were mass produced they are all different. Last reason is reducing extra casualties by making sure they don't miss when they fire or making firing weapons the last resort. And just for the movie's sake it would be boring as crap if they just blew the heads off in seconds.