This is wrong and I already posted why. Marines capable of dealing damage, regardless of kills, are far more valuable than dead ones. It also provides morale, and is one less corpse detracting from DEFCON. Not to mention if they were captured and killed, that "life" could have turned into 3+ larva for the xenos.
Considering I've never had issue with single weapons, I don't know how you would define "crippling." Having to manage two weapons and ammo types is by definition crippling. An MOU can cover short-to-medium range distances for shotguns. You don't need two weapon types.
Except that's not what it says at all and you're putting words in that aren't there. And being defibbed does not mean you're immediately put back into the round. Being delimbed, facehugged by a combat carrier, a punctured lung, or even damaged kidneys are all reasons you could need to be medevac'd. That's not including the heart damage from multiple defibs that requires surgery before you can even be revived (and yes, this happens regularly as someone who routinely plays medic/doctor).
In other words, throwing your life away in the hopes of rescuing a marine will frequently just produce two dead marines, making everyone's job that more difficult. That is of course, assuming you aren't captured in the process.