Can/should I call the police?

My ex and I have been split for a little over a month and have two under two. We were living with his family and I haven’t found another place so his family has been nice enough to let me stay. I was taking a shower to get my hair cut later and he came in there. He starts telling me how a relative’s death is triggering suicidal thoughts for him and is deeply upsetting him. So we were just talking back and forth a little bit. I forget what we were talking about but he made (what sounded like) a joke and was like “I’m gonna choke your ass out”. We joked like that when we were together so I didn’t think anything of it. So I said “okay go ahead” and he actually started to choke me. But it was nothing different then when we used to have sex so I thought that’s just where he was going. But then he also put his hand over my nose and was like “now you can’t breath”. In my head I froze and I wasn’t sure what was happening. So I just said “if I die, you have to take care of the kids by yourself then” and he was like “I’m okay with that. I got them”

It kind of scares me because the other day, his family asked if I was going for full custody and I said I wanted to. He hinted to me that he knew about it soon after and said “if ANYONE tries to keep them from me, I would kill them”. But when he said it, I just assumed it was a typical “dad response”