[PYA]

I'm not military myself, so the acronyms are gobbledygook to me, sorry.

Entry Level Separation or ELS is where someone gets removed from marine corps recruit training, and recommended for separation (termination) before their contract (8 years in terms of the corps) before 180 days.

Is that a bit like being medically discharged during training?

I'm familiar with the British army terms for the equivalent. Although, in some instances they may ask you to restart training (backsquadding) if you have certain conditions. I know a few people have been able to do that after shin splints and minor injuries. But if you have eczema you're categorically screwed because it classifies as an "open wound". I'd assume that would be true for the marines as well.

Some people on the way out were, but the difference is that if you get ELS you aren't entitled to any benefits.