I seem to have found a problem in plugin installation module - namely, I have 2 plugins bound to a project, RainLab.User and ShahiemSeymor.Roles. Roles depends on User and it's tables and performs some modifications on them. I have removed both plugins using CLI commands and then tried to reinstall them by updating plugins. October detected that both of plugins need installation and started installation. After unpacking them it failed miserably, as it started with installation of Roles plugin and did not find 'users' table from User. I could solve the problem via 'php artisan plugin:install RainLab.User' in CLI, but I think that some checkup on dependencies during installation should be performed. There was also no rollback on error, which resulted in Roles tabels being installed (partially I think, as there was no 'users' table at the time) and another error about Roles tables being already migrated after I pressed retry button.

If there is already such checkup, any ideas why did it crash?

This is interesting, I've not seen this yet. You may want to post this to github issues.