Poetically, Tali saves Shepard by pulling him onto the ship at the finale of Suicide Mission.
Run Background: Self-dubbed the "Survivor's Guilt" run, this game set out to have all crew but Tali dead by the end of ME3, with Shepard romancing her and surviving the high EMS Destroy ending, but having the cost in lives and crewmembers be as high as possible.
Overall goals were to have Wrex dead in ME1, Grunt still in stasis in ME2 & the genophage cure sabotaged in ME3, Kaiden dead in ME1 & Ashley dead in ME3, Rachni dead in both ME1 & ME3, and Legion handed over to Cerberus in ME2 & the Geth destroyed in ME3.
No upgrades to the ship ensured Jack, Garrus and Thane died on the approach to the Collector base. Choosing Jacob as the specialist ensures his death, not escorting Chackwas ensures her death, Mordin died due to having unloyal Miranda as the tunnels biotic, and Zaeed died as the secondary team leader. Unloyal Miranda is left behind to defend the rear and is killed. Because you apparently need two squadmates alive to survive Suicide Mission, Morinth is chosen with Tali for the final fight. Because she leaves before ME3 starts and appears as a lategame enemy in ME3, this still counts as effectively only having Tali left alive at the end of the game, save for characters like Liara, Javik, and James who are guaranteed to survive everything but low EMS endings.
