Summary
Five general caravan guards still standing. Three injured and out of action or partially out of action (no one has checked).
It looks like Calum has rejoined your side and it is probable his two compatriots will follow him. But your characters don't know all these details, so are less sure about this we are.
Then there are the three of you. So 5 + 3 + 3 makes it, maybe, 11 on your side to the, maybe, 7 bandits. It is hard to tell for sure.
Presumably all your fellow guards are converging on the front (and will sweep up Roncold and Fenslow). The more help they get from you, the PCs, the better they will fair, but that also puts you at more risk. Decide how much you are willing to put into this.