if thats the case, the 4 days shouldnt be a determinant here.

logically, if the prior notice is not signifigant, it should read
as
.... If your absence is due to
sudden illness, emergency or other unavoidable circumstances, you
must inform the institute, supported with documentary
evidence....
instead of
.... If your absence is due to
sudden illness, emergency or other unavoidable circumstances, you
must inform the institute in writing within four (4) calendar days
from the examinations, supported with documentary
evidence....