Can't remember if this is a two-part or three-part series, but each story centers around Tony, Clint, and Steve.
I remember in one story that the three of them are kidnapped in a giant underwater base and Steve is de-serumed. Near the end, Tony believes Clint and Steve to be dead and nearly dies himself on an oil rig when he avenges them.
The other one I remember opens up to Tony's point of view as his suited arm is being crushed and mangled before the three of them are left for dead in an abandoned missile silo. Clint had a bad concussion that rendered him nearly blind and Steve was weak and exhausted. At one point they had to climb up an elevator shaft but Tony could not do it thanks to his damaged arm. The silo is rigged to explode and they need to reach the top before that happens.
Please help and thank you so much.