"Vesuvius": my espresso machine experience

Today, my mom brought home an ESPRESSO MACHINE from my grandma's closet. (Not as cool or big as the one in the pic) Grandma could never get it to work right, but thought that since I worked as a barista for a while, i'd be able to get the hang of it. So i decided to try it out this evening...I was so excited, dreaming up new cappuccino recipies and wondering whether or not it was possible to have a "coffee duel" between here and Tasmania. Anyhow, i started it up, and was trying to clean it out...I actually did look at the instructions, and i don't usually do that. So, I put the water in, tightened up the lid, and turned on the steam. It wasn't quite working, so I took off a few of the parts from the frother and cleaned those out, then put them back on, and stood back, waiting for the steam cycle to go through. Good thing i stood back. It EXPLODED!!! it sounded like a freakin' GUNSHOT. I might have screamed. But i'm not telling. Mom ran out of the bedroom and saw me laughing and hyperventilating at the same time. Once she saw i was okay, she went back to bed, telling me to leave that thing alone. Well, I examined the damage....only the cap from the water reservoir had blown off...but it had spewed this AWFUL slimy stuff...all over the kitchen ceiling. Glad mom wasn't there for that...she would not have liked the word i said. Actually, on second thought, she'd probably have said something even better. At any rate, i cleaned the brown slime off the kitchen ceiling. Now i know why grandma couldn't get it to work. But at least it's really clean now...if i can ever get up the courage to use it again...golly!