The overall goal for a Engineer / Medic is to keep their squad alive. This is primarily achieved using the First Aid and Medicine abilities. Since the squad relies on you so much to keep them alive, you really need to have good survivability yourself as well.
Note that this build doesn’t use a Bonus Talent. I feel none of the Bonus Talents really add much to this class’s playstyle. In the Variations section I provide some Bonus Talents you can use, but I didn’t see much of a need when using this build.
12 Pistols (Unlocks Combat Armor, Marksman)
12 Combat Armor (Unlocks Shield Boost)
12 Decryption (Unlocks Sabotage, Hacking)
4 Hacking (Unlocks AI Hacking)
12 Electronics (Unlocks Overload, Damping talent)
4 Damping (Unlocks Damping skill)
12 First Aid (Unlocks Medicine)
12 Medicine (Unlocks Neural Shock)
12 Engineer / Medic
8 Charm / Intimidate
You will notice no Spectre Training in this build. While Unity is a really powerful ability, Medics are able to revive their squad with First Aid alone. Now Unity also boosts the shields of revived squad members, but I find a full health revive to be good enough. With your Medic specialization you will have a short First Aid cooldown as well, so you won’t ever be waiting for a cooldown to heal or revive your squad.
To keep yourself alive so you can use these abilities, max out Combat Armor. This talent also gives you the nice Shield Boost skill. Shield Boost synergizes with the Electronics shield capacity bonus nicely. With these high shields, you will rarely have to worry about health damage. In those cases Combat Armor will reduce some of the damage, and then you also have an excellent First Aid skill to rely on.
The remaining talents unlock and improve your tech skills. In this build, you are not able to max out Hacking and Damping, so your AI Hacking and Damping skills are weaker. This is the tradeoff for going along the Medic route. You don’t have quite as much tech prowess, but you do have good healing and survivability.
For this build, your primary damage comes from your Pistol. Marksman should be used whenever available except when you know a boss is coming up soon. Use your tech skills to disable enemies while you finish them off with your Pistols. Tech skills also launch tech proximity mines that do a small amount of damage in a radius. This damage can really add up if lots of enemies are grouped in a small area. Otherwise, the extra damage is a small supplement to your Pistol damage.
Shield Boost and First Aid are your primary survivability skills. Use Shield Boost as soon as your shields go down to stay in the fight. First Aid you would ideally use only when your shields are down and Shield Boost is on cooldown. However, your squad members usually need healing before you do. With your short First Aid cooldown, you can pretty much use it as much as you want. Just make sure you don’t use up all your medi-gel. Try to have a minimum of 3 for boss fights, so limit your use if you know a boss fight is soon.
For this build you want healing and survivability. None of the Bonus Talents help with healing, but there are a few that help survivability. Hacking and Damping are your lower tech talents, so it’s easier to remove points from them than to other tech talents. This gives you 8 talent points to spend in your Bonus Talent.
Barrier instead of Hacking and Damping – You can sacrifice a few tech talents in exchange for more survivability. Barrier tacks on shields like Electronics just only for a short duration. It’s a great boost in boss fights. You can take a direct hit from a rocket and survive.
Lift, Singularity, or Stasis instead of Hacking and Damping – All of these biotic skills disable enemies to some degree. Lift and Singularity both force enemies into the air where they can’t do anything until the biotics drop them back down. Stasis freezes an enemy for a short time, but makes them immune to damage. It’s good for a divide and conquer strategy, but then you have to be careful not to waste valuable tech skills on a Stasis’ed enemy.