How to deal with two year old temper tantrums when you have no time!?

So my daughter is 2.5 and has started having meltdowns as soon as we really need to go somewhere. Like an appointment or daycare and we try everything in the books to get this girl out the door but then as soon as we close the door behind us she goes mental and starts flailing around in her stroller or on the floor screaming, back arching like she's being murdered. This is kind of new for us and we live in a busy apartment complex and I am so petrified of everyone staring at us like we are kidnapping her or something so we go back inside and deal with the tantrum there. Today though, it was so out of control it took an hour of putting her in time out until she was too exhausted and we could finally go. I was an hour late for work and so mentally exhausted I just feel miserable. Can anyone help give me examples how you would deal with this? I have huge anxiety about her having a meltdown in public, is there any way to avoid that!?!