One of the most important thing to consider would be that our Holy Prophet pbuh who did even not curse his worst enemies came out in a state when he was sick to chase everyone except a few out of Medina & cursed those who disobeyed him & did not leave Medina at once.
"Make haste in joining Usamah's legion. May Allah curse whoever fags behind Usamah's army."
We all know that Abu Bakr and Umar were both supposed to be in that army under an eighteen year old which means they disobeyed the direct orders of the Prophet pbuh and were part of those who were cursed by the Prophet. Just imagine what is going to happen to those who are cursed by the Holy Prophet pbuh.
Now the point to consider is why would our Prophet pbuh take so much pain to make sure everyone he wanted was out of Medina in his final days?
Could it be that he envisaged something like Saqifa happening that he wanted to make it a clear ground for Imam Ali's elevation?