I really liked it! The aesthetics were clean and well polished, and the premise reminded me a lot of setting up for a Payday heist. You've got a lot of room for expanding based on secrets and weird layouts.
I understand why the clock ticks down and that putting a time limit on it really helps rush the player, but it did affect my enjoyment a little. My one suggestion is you could mix in some levels where the clock counts up instead of down, and then penalise players for taking too long. But I totally get why it's there.