That's stretching the definition of heartbeat. A heartbeat is OT in Game 7. Not down 3-1, and lose in 6.
Here's your deadline fun; Cogliano, Comeau, Oleksiak.
Nobody is taking a soon to be 35 year old Khudobin, whose cash exceeds his cap hit the next 2 years. Pavelski can pick where he wants to go, and is probably cool with the extra money he makes in Texas. Obviously nobody is touching Benn and Seguin because of those contracts. Klingberg could be traded in the summer.
They're too far gone with Benn and Seguin to blow anything up. Not that you can blow things up quickly in a hard cap league. They'll take their lumps this year. They didn't go all in on Pavelski just to get rid of him. They clear out some space this summer. Most of it will end up going to Heiskanen, but they'll give it one more shot with Pavelski, Radulov, and Klingberg. After 21-22, those 3 are UFAs, and they take up a good chunk of space. Then they'll do something else to try and win with Benn and Seguin, because what else are they going to do? If they suck, they suck, and they get a higher pick, but they're locked into those two guys. There's no rebuilding yet in Dallas. That comes 3 or 4 years from now, when Benn is done, and assuming they've been in the black hole during that time.
Teams don't just rebuild. You fall apart over a period of years, and/or players choose to leave. That's when the rebuilding starts. Teams generally hold onto any shred of hope of being competitive. Vancouver with the twins. Calgary with Iginla. NJ wasn't rebuilding until after Parise walked away. Buffalo began their current crumbling after Drury and Briere left. SJ is now rebuilding, but they weren't trying to, and now they're stuck with a handful of terrible contracts. The Rangers publicly said they were rebuilding, and then soon after signed Panarin to a billion dollars. That's not the investment of a rebuilding team.
Dallas is nowhere near rebuilding anything. At best it's a retooling, and anyone with any value in a trade is younger, which are the guys they can't afford to trade.