I was trying to get a sub-26, not anywhere near 25s. I always took out the cave entrance explosives for a safe-ish path to Romanova, but somehow she got taken out be the explosives.

I was relying on the game damaging her with the explosives (explosive domino effect, shrapnel impact, guards' rockets exploding near her, or a combination of the three) to only have to 2-shot her (possibly using the Hothead for extra damage), not killing her for me.

Apart from double-checking the routing, the only thing left I can think of right now is to use the Hothead (bigger radius may help the domino effect) to destroy the explosives and pray for good luck. This actually makes the IL mechanically far less frustrating but becomes mostly a lottery as far as I can tell.

But Romanova is now faster than Mikhailov, interestingly.

(Xbox 360 disc played on Xbox One S)