From the book Africa's Commandos extracts from an article by the RMO (Regimental Medical Officer) on the use of an MRU:

Mobile Resuscitation Unit – the RLI lifesaver
By Cliff Webster

... The 1973 Arab-Israeli War and the then-recent Vietnam War had amply demonstrated the value of casualties receiving quick access to resuscitation and stabilization before transfer to major medical units for specialist attention. This required the medical personnel getting to the casualty in the field as soon as possible to commence resuscitation. The sooner the casualties received intravenous resuscitation fluids the better, whether in the field and/or on arrival at the MRU. During these years the international term ‘golden hour’ was coined. It referred to that critical hour after serious injury during which resuscitation should ideally commence to ensure a good outcome for the casualty. The MRU was frequently well within an hour’s helicopter flight from the battlefield. (both located in Salisbury, now Harare)...

... The MRU was often deployed next to a forward airfield so that fixed-wing aircraft could be made immediately available to transfer casualties back to a central hospital once they were stabilized in the MRU, usually to the Andrew Fleming Hospital via New Sarum Air Base. ...

... Injuries were broadly classified into the following groups (medevacs included):

Injury Groups.....................Number.....Percentage
Superficial injuries.................127.......... 39.1%
Orthopaedic injuries..............100...........30.8%
Multiple trauma......................24............7.4%
Burns...................................16........ ....4.9%
Head injuries.........................11............3.4 %
Chest injuries........................11............3.4%
Abdominal injuries..................11............3.4%
Other (e.g. ENT).....................8............2.5%
Medevacs............................17............ 5.1%
...

Note: in the terminology of the time the term 'MEDEVAC' (medical evacuation) related to evacuations related to sickness and disease - as opposed to CASEVAC (casualty evacuation) which included all war wounds and related injuries.

...

Of the 325 persons who were casevaced and medivaced through or from the MRU, two died en route to the MRU, two died as they arrived at the MRU and two died en route to a central hospital from the MRU. Three of these cases were multiple trauma cases, one was a gunshot wound (GSW) to the thigh with femoral artery severed, and two were GSWs through the base of the skull. This was a 1.8% death rate which emphasized the value of having such a unit in the forward area as there were clearly cases which would not have survived the long trip to a central hospital without stabilization. Sometimes the RLI MRU was close enough to a Fire Force contact to see and hear the K-Car over the contact. On a couple of occasions we received at the MRU, or were able to get to, critically injured troops within 7–10 minutes of them being hit.

In conclusion it can be said that the RLI MRU more than paid for itself as a lifesaver and also as a morale booster.