0: Edit the original thread to apply your fix instead of posting a comment that tries to fix it. In worst case scenario, if this knowledge isn't applied, you'll find yourself fixing tiny little typos by commenting several different comments trying to figure out how to spell an obscure word.
1: Let the Grineer trigger the alarm. Lotus will tell you when she detects a Prosecutor. Be advised that they are immune to all but elemental attacks, so mod for every elemental you can on every weapon (i.e: Corrosive + Heat on Primary, Gas + Magnetic for Secondary, and Radiation + Viral for melee).
2: Do not rush through the mission. This is easier on a Capture mission, since killing enemies after target capture is entirely optional.
3: If possible, go slow enough so that enough Prosecutors spawn, die from being killed, and drop Javlok Capacitors which are essential to the construction of my favourite speargun.
Koldraxon-732's post in Prosecutors Mars>Jupiter was marked as the answer