Based on the sneak peek of The Flash 3x22 Infantino Street, and is basically my take on what could have happened once Snart got back to 2016 if the Legends realised something was up.
Hey, Snart, is that…blood?" Mick asked as Leonard got back aboard the Wave Rider. He'd just returned to 2017 Central City and saving the day with Barry, helping the Flash to steal the Dominator's power supply to fuel the speed force cannon.
"So what if it is?" Snart challenged him as the rest of the Legends looked over at the two criminals.
"Where did you get it from? Why wasn't I there?" Mick asked.
"Yes, Mr Snart, I too wonder why you've suddenly got blood on your hands and chest." Rip Hunter asked.
"It's a long story, Captain, and I don't feel like it." Snart shot as the others began to pay attention.
"Now I'm curious." Jax said.
"Yeah, I think we'd all like to know what's going on." Sara said to Leonard.
"Alright, fine, I was outside and I got approached to help with a heist, we did the heist, I'm back, the end." Snart said.
"How? Who would possibly know you're here?" Ray asked him.
"The Flash, apparently knows where we are. It was him." Snart told them.
"Barry?"
"Mr Allen?"
"Red?" Mick asked, surprised. "Why would he want or need a heist?"
"He came from May 2017, he needed my help to steal something from ARGUS, apparently his fiancé, Miss West, will die if he doesn't stop another speedster, and he needed the thing from ARGUS to stop the speedster." Snart told them.
"Why come to now though?" Ray asked, frowning. Why would Barry be willing to steal, aren't they friends with ARGUS?
"He wouldn't say anything, but I could tell from the expressions of Team Flash, I'm dead by May 2017." Snart told them.
"Its dangerous to know anything about your future, why would Mr Allen risk it?" Rip asked aloud.
"Probably due to the threat of Savitar." Gideon informed them.
"Savitar?" Everyone asked.
"A speedster from the future who came to threaten Mr Allen in 2016. He killed Iris West in May 2017, before he was eventually stopped by Mr Allen. However, the events that led to his defeat also caused his rise." Gideon stated.
"What do you mean?" Kendra asked.
"Barry Allen created Time Remnants to deal with Savitar, whom were all killed except for one. This Time Remnant headed to the past and became Savitar. Barry Allen is Savitar." Gideon informed them.
"So Red killed his girl, huh?" Mick asked with an arched eyebrow as the others looked shocked.
"No, Barry brought me to save her, I could see the love in his eyes for her." Snart said, surprising them all. "Savitar is a warped future, not Barry Allen. Barry would die for Miss West, he isn't Savitar and would never kill her." He stated.
"As charming as all of this is, however, there is the matter of we all know the future." Rip said as the rest looked to one another. It was true, now that they knew the future, at least in some extent, could they change it for the better?
"Is there a way to act on this information?" Stein asked.
"No!" Rip said.
"We can't forget it though." Ray said.
"Oh?" Gideon asked before a pulsing blue light appeared, disorientating the entire team. As they blinked and cleared the shock from their eyes, they looked around.
"Hey, Snart." Mick said. "Is that blood?"
"So it is." Snart remarked. "Not sure where from though."