I've always considered that Medikits are something like a box of those square white bandages, with a built-in stimulant ampule, that dispenses when you slap it on. Which means that while they might be 'saved' with a medikit in the field, once all the aliens are defeated and you're not being shot at/in fear for your life, you can focus and pay some more proper attention to various wounds and injuries.
So you might triage in the field, but once you've got them back to the dropship, you have some slightly more potent recovery tools at your disposal. Not a full hospital, but something like an ambulance, so it's not 'only what can be done with what I have'.