[X] Homura will shoot familiars as they near her and as they swarm Mami & Archer. When they inevitably group up together in their swarms, use explosives.
[X] (Archer) Kill the witch in a barrage of arrows, coordinating with Mami to entrap the witch between their bursts of fire. If the small stuff doesn't work, Caladbolg II it after goading it to a safe enough distance away from the masters by firing arrows.
-[X] If the Witch targets Homura, ask her if she can act as bait and then timestop away from it as soon as Archer unleashes the artillery.
Well, this witch and her minions look like they'll be fun. At least, as fun as the cannibal nightmares of a little girl's soul can be.
The witch launches a flurry of tendrils at Tomoe-san, only for Archer to hack and slash at the offending appendages before they can reach their destination. The witch screams in pain, and the familiars charge your allies. You unload your Howa's magazine into the incoming swarm until you hear the rifle click empty. You toss the rifle aside, and rush off to take a flanking position as your allies engage the witch.
Taking up this new position gives you a better line of sight on the advancing familiars. One, two; two grenades you toss into their ranks, causing their drinking-bird bodies to erupt in a burst of shrapnel. As the rest of the horde reforms the line, you pull out something a little bigger than the Howa- the FN M249 squad automatic weapon. Bracing yourself, you fire in bursts, watching the two-hundred round belt flap as rounds are fed into and ejected out of the weapon at breakneck speed, tearing through the swarms of familiars as they attempt to advance on you and your allies.
Speaking of your allies, they seem to be doing an admirable job against the witch. The pair alternate their fire, forcing the witch into the other's line of sight. Between Archer's barrages of arrows, and Tomoe-san's three-line formation, the pair is keeping up the pressure, and you wonder whether Tomoe-san would have been better served with the Archer servant than you. Given your own tactics, you would guess that Assassin would have been the best fit for you in the Holy Grail War of a different lifetime.
Now isn't the time to be lost in thought. Your FN's barrel is smoking and it's run out of ammunition. You toss it aside, throwing another grenade into the largest cluster of familiars as you withdraw another Howa rifle from within your shield, and open fire yet again.
And then! A brilliant flash of crimson lights up the labyrinth as Archer's heavy arrow pierces clear through the witch's center mass, tearing it asunder. Just like that, the labyrinth and all its unnatural contents fade away into nothingness, depositing you and your allies back into the parking lot.
"Well, all things considered, I think that went rather well," Tomoe-san says, dispelling the last of her ribbonwork muskets. "Akemi-san, Archer, you both did admirable work."
You accept Tomoe-san's compliment, but Archer has something else on his mind when he asks "Master, just how expensive is it for you to fight like that? Each one of your firearms costs the Japanese government hundreds of thousands of Yen; and you just throw them away when you're done with them?"
You shrug. "It's usually easier for me to throw one away and grab a new one than it is for me to reload. I've never paid much attention to the cost."
"Don't you think that's a little reckless? What if one of them winds up in the wrong hands? What if someone commits a crime using a firearm that you threw out?"
"Archer is right, Akemi-san," Tomoe-san chimes in with her support of Archer's concerns. "You've already committed a serious crime in stealing that much hardware from the Self-Defense Force, and yet you're so careless about tossing them aside when you're done with them. I would really prefer that you adopt more practical tactics in the future, or that you might actually put to use that bow you've been working on."
Two against one; you sigh, resigning yourself to their admittedly better judgement. "Very well. If it will make the both of you feel better, I shall try to be more judicious with the disposal of my firearms in the future."
Tomoe-san smiles faintly at you, saying "Thank you, Akemi-san. That's all we ask." Tomoe-san goes to pick up the Grief Seed dropped by the witch, offering it to you. You refuse.
"All I did was shoot out the familiars. You and Archer were the ones responsible for killing the witch, and Archer has no need for Grief Seeds. You can have it."
"Are you sure?" You nod, showing your Soul Gem to Tomoe-san. Faint slivers of black threaten the fringes of the jewel, but the majority of the amethyst stone remains unmarred by corruption. Tomoe-san nods, pocketing the spoils for herself. "Very well, Akemi-san. However, the next one is yours. I shan't take no for an answer."
You accept her terms, saying only "It's late, and we have a busy day ahead of us tomorrow. We should retire for the night." Tomoe-san nods, accepting your terms in kind, and the three of you part ways here.
Tomorrow shall be a busy day indeed.