Jazz,
The guy who surveyed and calculated the radar vectoring chart is often the same guy that surveyed and calculated the MSA.
Everything in 8168 assumes that all engines are operating and it is up to the operator to come up with any OEI procedures it needs.
From what I can see, despite ATC responsibilities while vectoring, ATC have no responsibility as soon as you loose an engine and can no longer make the required terrain clearance i.e. ATC vector on the basis of all engines operating all the time and when one stops ATC simply holds up it's hands and say - we are no longer responsible sort yourself out using your own procedure.
What Malaga makes intersting is that the MSA seems to make the appropriate extra clearance from high terrain (+2000ft) while the radar chart in the same place seems to only use 1000ft.
Regards,
DFC