Stealth only works if you standing still, move too fast and you are visible on Radar and a PR user can tune into you.
Stealth works if you are not sprinting or jumping. You could be phased if you are in plain sight, if you were sprinting or jumping and they tuned you, or if you are standing by someone who gets shot and you were in the firing line.
Make sure you are using supercharger because it helps your non sprinting speed too.
More people are killed by donkeys annually than are killed in plane crashes.