Commander Okay guys. The Zerg rush is coming faster than we thought. I’m going to need four guys-quick! *Pause.* Commander Hello? Guys in the barracks? Marine I won’t shoot anyone until I get some minerals. Commander What? Marauder Me too! And I want gas. Commander Why do you want- Marauder I require more vespene gas. Commander That makes no sense. And how do you want me to deliver you gas? And why? Marine Fact is we need minerals. Commander We are all going to die if you don’t shoot them. Marine You gonna give me orders? Commander Yes! Stop asking that! Look, there are literally tens of thousands minerals on this map, can you just kill them all and go get stuff later? Marine No. Commander Fine. How many minerals? Marine Fifty. Commander Okay, I have 200. Come on, four guys! Let’s go! Marine Wait! One at a time. Sometimes two. Union stuff. Commander Come on! Marine Hold on! I need thirty seconds to be trained! Commander That is way too long! Also way, way not enough training. Somehow it’s a disaster in both directions. All cause of your stupid union and minerals. It makes no sense! Forget the minerals! Marine Why can’t you just send in the SCV’s? They’re armored cutting machines. Commander But they’ll all die! And then we won’t be able to get…any… Marine … Commander uh… Marine You lying bastard.
I've always wondered about SCVs. They are armored, and fusion cutter like an extremely potent weapon. Real-world side of it, some deep mining machines have pretty much literal armor plating that rivals some military applications due to intense pressure and heat.
Also, they're actually about twice as tall as marines and the drill they use is almost the size of a Zergling.