Cool interpretation of the theme, having to choose whether to risk defusing the bomb or leaving it. You have the main gameplay loop nicely implemented and I hope you can further expand this idea! There are some directions you could think of pursuing since you mentioned that you wanted to turn it into a full game: adding different items/weapons, creating some varied enemies (melee/range), talking/knocking on doors could have the civilian evacuate etc.
Viewing post in Countdown Crisis jam comments
Ah I tried interacting with the civilian twice and both times they refused to leave, so I thought that it wasn't implemented and they just wasted the countdown timer :D Then in that case, having the means to skip through the dialogues would be good, or maybe having some way to allow the player to persuade them to evacuate.