Not exactly. Everyone in a group (however the commisaires choose to define that) at the finish is given the same time. If the field splits into multiple groups, each group is given the time of the lead rider of that group. Only if a rider or riders have a mishap in the final 3 km, those riders get the same time as the group they were in at the time of the mishap. It is perfectly possible to lose time in the final 3 km. In fact there's a very good chance we'll see it happen tomorrow (Friday).