Is it okay to leave a sleeping baby at home while you run out for a quick errand nearby?

A big no. Anything could happen in a split second. I remember one time I put a DIY headband on my 2month old LO. she was sleeping soundly when I tried to put it on. Left it on her head to check my laundry when I get back after not more than 10secs the band was already covering her face! she looked cute tho looking like a pirate but it could have been worse...