Taking apart mini fridge Help!

Ok im taking my mini fridge apart for a phase change system im goin to build and all the sudden i hear a hissing sound, this is normal right? im not goin to blow up anything am i?

you prolly cracked a line open. move it to a well ventilated area if possible, and let it release all of it's preasure. then it will be safe to continue tearing down. you will have to reseal the system and recharge it, but that should be obvious, since you're buildin a phase change.