Hello there, glad to know that you've been enjoying the game, and thanks for taking the time to post a bug report! We'll need to look at the crash logs to know what's caused the game to crash when you were equipping said soldier. If you relaunch the game after a crash, it should prompt to generate a bug report file. Said bug report file should be in \Documents\My Games\Xenonauts 2\BugReports. If you can attach the bug report .zip file when making a reply, we'll be able to give it a look.