Fighting in a mech is one of the most hostile environments a soldier can encounter. To even get in, you need implants, a restraint suit, enhancement shots, traditional human rituals have not yet caught up with such a life.
And there is simultaneously too much information and too little left.
You know immediately when someone in your squadron's bought it. Their "little SIS" or "Soldier Information System" flatlines, they drop off radar, lidar no longer pings, FLIR spins helplessly for an ID panel, and a voice on the radio goes silent. Unlike the infantry, there's nothing, not even a dog tag.
In orbit, you rarely have enough delta-v to waste on something as minor as what used to be a comrade.
Even planetside, the sheer violence of the modern battlefield rarely leaves much. The smallest caliber weapon is the "Grad" or "Hailstorm" 23mm autopistol.
On average you're deploying with something like a 57mm heavy autorifle, a 14.5mm hypervelocity coilgun, or a 45mm plasma canister launcher. Dumb rockets, including laser guided, start at 70mm, smart missiles usually start at 100mm and seek cockpits like rabid animals.
Once the ablative and reactive armor is off, dumb rounds beat pilots to death inside their steel-self. When lead impacts the thick armor, they rarely carry enough kinetic energy to penetrate, but they badly shake the cockpit. It will eventually exceed the ability of the mech to shield its pilot from the forces involved. If the mech can be retrieved, this kind of casualty is referred to as a "hose" casualty, because they have to clean the pilot out with a pressure washer.
Hypervelocity needles leave clean holes but even a glancing blow to the cockpit produces incredible forces. They are an exotic mix of compressed metals for maximum effect on target, upon entering the cockpit, an action that at those speeds takes a microsecond, the parts of armor pushed aside are also moving at that speed, and a depleted uranium "effects layer" means they burst into flame upon contact with the oxygenated cockpit. You know you've made a good hit when the exit leaves a jet of flame. The entire cockpit is modular because there's nothing left but ash.
Smart missiles rely on the chemical route to hypervelocity. A planetside chemical plant ravaged gaseous nitrogen with lightning until they were shoved into a raging hot molecule that aches to return to its original atmospheric form. This transition happens between Mach 15 and Mach 20 and accelerates a metal liner to that speed near instantaneously. This creates a "spall cone" of fragments pushed inside that shred the pilot and often a fuel line, immolating them. A smart round hit creates a thoowp as it cremates the cockpit.
Plasma canister rounds are relatively new, but just as devastating. They combine the extreme heat of explosions with the massive overpressure and blast energies of a barely contained plasma toroid cracking atmosphere. Once it's heated by the magnetron, a blast of compressed air knocks it out, and a rocket booster made of nitrocellulose with zirconium staples knocks it to its final supersonic speed. Upon impact, it melts away reactive armor before pushing the structure in, creates a blast of electromagnetic energy, and crushes cockpits completely. Another job for a pressure washer.
Once you return to the railhead, you march to the barracks, find their sleep chair and locker, and tear it apart. Everything frivolously personal is trashed, superstitious pilots even toss the bedding. Anything more important is given to the officer who sends it home.
In a few days, fresh faces will arrive with the supply train and they bring new bedding, new personal items, and you reset a counter on the whiteboard, the one tracking their Lifetime Mechanization Limit, higher than everyone else's.
Depending on your own LML, it might not be worth learning their new pilots' names. You're counting your own LML, sorties until you can go home, unless you too end up in the trash can and a cardboard box with a cellophane wrapped flag and an officer's form letter.
