Crack safes, grab loose cash, dodge the police, and reach the getaway door before the vault locks down.
Doodle Heist runs on a heat system instead of a fixed difficulty curve. Grabbing loose cash off the floor is instant and risk-free, but cracking one of the vault's safes takes real time standing still next to it -- and both cracking safes and time itself steadily raise your heat level. Once heat is high enough, police start actually spawning and coming for you.
You can shoot back at responding police or just dodge them, but the real decision every heist forces is when to stop pushing for more loot and head for the getaway door -- reaching it banks whatever you're carrying immediately, at any point in the run. Get caught, or run out of time before you extract, and you lose everything you were carrying, safes cracked and all.
There's no bonus for cracking every safe in one run -- heat only goes up the longer you push, so it's usually smarter to bank a partial haul through the getaway door than to gamble on one more safe once police are already responding. Loose cash piles are free money with zero heat cost, so sweeping the floor for cash between safes is a low-risk way to pad your haul while you decide whether it's time to extract.
Heat rises both from cracking safes and simply from time passing while you're in the vault. Once it crosses a threshold, police start spawning and actively coming after you -- grabbing loose cash off the floor does not raise heat at all.
You lose everything you were carrying -- all the loot from cracked safes and grabbed cash on that run is gone. The only way to keep your haul is to reach the green getaway door before you're caught or time runs out.
Yes, and it's often the smart play -- the getaway door is live the entire run, so you can bank whatever loot you're carrying at any point rather than being forced to either clear everything or lose it all.