Mean boss

I don’t know what’s wrong with him and I’ve never met anyone like this before. He’s not my direct boss. I only ever deal with him in passing, like tonight I worked closing so I got locked in and he has to unlock the doors. He is always incredibly rude, I don’t know if he hates his job but he just seems to because of how rude and disrespectful he is, his attitude is awful always seems annoyed and irritated. Tonight I had to call for him to unlock the doors and he answered his phone by telling me to speak with a very rude tone and he liked said something under his breathe like “lock n unlock the doors again but that’d piss me off even more” to me he just seems to have a really bad attitude and is always pissed of, I’m sorry but if you hate your job this much quit and find another or don’t take it out on employees who don’t even speak to you, I’ve been there 6 months and only “spoke” to him 2x tonight and another night awhile ago. I don’t know I just feel bad cause he was mean to me and it’s hard for me to let this roll off my back.