It is not as if the border staff have their feet up. Any processing of one person will mean the processing of others can’t happen. The capacity of the border staff is finite and there are ever more Ukrainians and EU citizens arriving at the borders too. My experience is that Shehyni-Medyka can process about four-six people on foot at once at both the Ukrainian border and Polish border heading into Poland. I imagine they have all the border staff they can there working.
Again, every sympathy with people trying to flee this now, but I have zero surprise that those that chose to stay, and are only attempting to leave now, will be having serious problems leaving. I would completely expect EU citizens and Ukrainian citizens to be given priority over me if I arrived at the border now.
People on the Ukrainian-Polish border are relatively safe though, even if in poor comfort. If they were in any immediate danger, I imagine policy would immediately change and the floodgates would open.