Hi Pascal .
I suppose its difficult to tell , if they had left at 3.30 which I dont think they could have ! , possibly thay may have got as far as 1 or 1 1/2 km's , as they would have had the wagon to carry the sick / injured / wounded , but as there was only the one wagon ?? , they couldnt have left anyway - as all those who couldnt walk would have been to many for one wagon . Hope this makes some sense !.