In these multi sector, 25 minute turnaround days, things like this are going to happen. Starting the engines while the PNF is doing a before start cx list (that'll be a hot start and a blown engine then!) , taxi clearance to get ahead of the 4 other aircraft on pushback without even completing engine start or the cx list. And with this happening, it's very easy to lose the SOP sequence and miss something vital........
It's up to the Captain primarily to set an example for this reason.