Its always wise to go with your ''gut feeling'' if you don't feel good about it, WALK AWAY TO LIVE ANOTHER DAY!!
I never used to worry about it to much until I got hit, not bad but enough. Rarely do I watch the saw now mostly look up but I have occasionally cut in more than I should have.
I'm not so worried about something coming down when cutting....everything after that is sketchy. Those standing dead tops will explode when they hit the ground or hang up in another tree. Once the tree is going I'm getting as far away as I can. Just hum this tune and you'll be fine.