About the MGs, another solution is to set the armour of the MG at a low level, so that after killing the gunner they will fire at the MG and destroy it in less time. I think it's a good solution in a matter of realism: destroing an MG is not a stupid thing to do, it prevents other to use it and if you have several guys firing at it it will be destroied fast.
And, about the guy running away I agree with Der_Richter, it should be up to the team leader to keep his men together. Anyway, it's strange to see men abandoning formation without "Engage at will" been issued.
Simon