Are they really capable of murder?

So I saw a post by a guy in another subreddit who was stabbed by his ex and barely survived. He needed multiple surgeries and was on an ICU. His ex had BPD and he was aware of it. She got 10 years in prison as part of a plea deal because she admitted to it all.

Are people with BPD capable of murder or was it maybe another mental illness? Have any of you been in situations where you actually got physically hurt of feared you would?