The soldiers outside the tomb kept vigilant watch, half of them on watch while the other half slept, turn and turn about, every three hours.  As darkness fell, they remained on extra high alert for any Galilean gang creeping up.  If anything untoward happened or anyone sneaked by them, they would be executed, either as a squad or by one picked out by lot to answer the crime of all.  There was no chance they would doze off.