This may not be the best post to “first reply” to, but it is the one that pulled me out of the shadows I was lurking in and it may give you a glimpse of my brain so you all can determine whether I am bb-worthy or not, so here goes:
First: cars do not tend to spontaneously combust. Therefore there was either a catastrophe or it was deliberately set. Which leaves two reasons the adults have not extricated themselves: they are too injured, or it is by choice.
Regardless, I go to the back first and grab the baby – with the door open, the dog can get itself out unless it’s strapped in, in which case it may be “sorry, dog”. Though if it will take less than a second to free it, might as well, because that less than a second won’t change much in the end.
Baby first for multiple reasons:
it is the least responsible for the current predicament. If this was by catastrophe, the baby had no way to avoid or mitigate it, as opposed to an adult (esp. the driver). If the fire is actions of an unknown third party (is this a drug gang hit), baby did not choose to involve themselves. Same if the adults remain via choice (family suicide).
toxic chemical exposure tends to hit infants harder.
the baby is too young to form memories (specified baby, not toddler) so will suffer least psychological damage.
The next rescue depends on context. If it is obvious that the adults are staying due to injury or incapacitation, start with whichever one is either least trapped or injured (opening the door on the same side as I started). Then return for the other. If, however, it is clear that one or more of the adults was CAPABLE of escape but chooses not to (especially if they indicated deliberate culpability) , then I might just be angry enough to save the dog who didn’t get to choose a firey death. Or, if one of the adults cannot be extricated in time, the dog.
TL;DR Baby first, then it depends on circumstances. Humans first if all else is equal, but there may be some cases where I would save the dog. My mind gets a little dark at times.
Oh and FTR: I am not saying anyone DESERVES a horrible fate, but if forced to choose, I would say the most culpable have the most responsibility for the consequences of their actions. As would I with my choices on who to save.