Ward of Hearts

The psychiatric hospital Silas is trapped inside runs on rules, and every room has one that kills you for breaking it. Everything walking the halls is rated S-Class, meaning nothing in the building is survivable by fighting it. He has worked out that he is going to die there when a Romance Conquest System switches on in his head. It rewrites what he is facing. The monsters become people he is supposed to win over. The traps that were built to kill him turn into dating scenarios he has to get through. So Silas walks a ward designed to destroy him and tries to charm the things in it, because the system has decided that is how he stays alive. Whether that works depends on whether the hospital's rules or the system's rules turn out to be the ones that matter.